Death of Unity - The Fulgrimian Heresy

by Tanner151

Ten thousand years have passed since Fulgrim's Heresy was defeated, and the threats facing the Imperium grow as the centuries grind onward. Xenos, witches, heretics and worse plague the Emperor's Realm, but they are but secondary concerns. In the Eye of Terror, the Traitor Legions prepare for their final crusade of vengeance. It is the 41st Millennium and there is only war.

37. Thousand Sons

Thousand Sons Index

Knowledge through Sacrifice

"There is no sin but ignorance."

-Magnus the Red

"The minds of gods are not for mortals to know or to judge. Accept that Tzeentch has a place for all of us in his grand scheme, and be happy in the part you have to play."

Excerpt from the Book of Magnus

"Long ago I sought truth, yearned for it even. Across a hundred worlds and a thousand cultures, I looked for what held the universe together as if it were a canvas, peering past the veil into what lay under. Never did I think something would stare back. I warned Magnus of the dangers but he took no heed, confident in himself and his abilities. His self-assuredness swayed and blinded me to his fatal flaw: hubris. Perhaps if I saw it I could have prevented our fall from grace, or perhaps my intervention would have accomplished nothing. Fate is a tricky thing, ever changing like a coursing river, and like a river one can drown in its currents, pulled to the depths to die if not careful."

-Amon, Captain of the Ninth Fellowship and Equerry to the primarch

---

Origin-

The unknown has always been a prevalent fear of Mankind. That unquenchable, raw fear of not knowing whatever resided in the dark has hung over humanity since its birth. While many are dire and destructive, few fears have caused as much dread and paranoia as that concerning the psyker breed. Psykers have existed among Mankind for tens of thousands of years, hailing from the dawn of the species but only since M22 have their numbers grown exponentially and so did the threat their abnormalities posed. Though persecuted on many worlds, hunted as witches and burned at the stake for the crime of having their gift, many worlds welcomed this new evolution of humanity, establishing universities and encouraging the development of their powers for the betterment of all. In spite of the burgeoning acceptance psykers were receiving across much of human space, there was still widespread persecution where they were treated as second-class citizens at best but more commonly hunted down and murdered.

As a result of the persecution assailing them, hundreds of thousands of psykers, as well as those physically mutated, from various worlds came together and chose to migrate elsewhere, searching for a home that would become a safe haven for their kind. The migration fleet only grew as more joined the expedition, fleeing bigotry and misunderstanding. Years passed, suitable worlds bypassed either due to already being colonised by Mankind or under the thrall of xenos, and soon enough morale began to plummet as time went on. One by one the fleet's amassed voidships departed, leaving for worlds that accepted them or trying to find sanctuary on their own volition. Soon the fleet had shrunk to less than a dozen vessels. It would be these last few that would discover in a remote Ultima Segmentum star system near the galactic core, after a random warp-jump, an arid world of vast deserts, fertile deltas, and beautiful oceans. The fleet surveyed the world, finding it able to support life and seemingly free of natives or hostile species, agreed to settle upon it, eagerly noting it for its isolation from other human-controlled star systems. Due to its isolation and lack of sufficient natural resources the psyker-mutant population felt that they would remain safe and be allowed to thrive in peace.

Believing this world to be what they had so long sought, the fleet settled onto the planet, naming it Prospero, breaking apart their starships upon landing to develop their initial infrastructure, and there they flourished… for a time. Centuries of peace and prosperity passed, great cities constructed and the study of psykers and the Immaterium continued unabated with significant strides made and catalogued. Disaster, however, soon made itself known in the form of Old Night. The Age of Strife, a time of increased and deadly warp storms, wracked the galaxy, destroying the galactic-spanning human empire and pushing Mankind towards extinction's brink.

While most worlds descended into anarchy, either by warp-maddened psykers leading tyrannical regimes or endless war over scarce resources like what would occur on Terra for centuries, Prospero was spared this horror, at least initially. While civil stability was stringently maintained, there were several incidents of psykers becoming corrupted by the Great Ocean's power and subsequently killed by their fellows to prevent their madness from spreading. For years this ensured Prospero remained a safe and stable world, a seed of safety amidst a galaxy of horror. But that changed immediately with the arrival of the psychneuein.

From the deep deserts emerged a warp-based parasitical xenos that overran city after city, nearly impossible to fight with conventional means. The xenos parasites implanted eggs in their hosts' brains and from the victim's violent and painful death the xenos multiplied in their dozens. In later years, Imperial and Prosperine scholars debated about whether if the psychneuein were native to Prospero and awoke due to the Immaterium's turmoil or that the parasites were able to pierce the world's thinned veil of reality to infest the planet. Regardless of their origins, the xenos quickly overran much of Prospero, with only a handful of major cities able to deny the psychneuein, using telekinetic barriers, arcane rituals, and unforgiving containment procedures to protect the cities and surrounding farmland. This resulted in a stalemate; the humans trapped within their cities while the alien parasites hungrily roamed the desolate wastes of Prospero in search of prey.

This continued for thousands of years, with the enclave-cities surviving but at great cost, lamenting their effectual imprisonment within the protected borders for few dared and even fewer survived the journey between cities. Yet by late M30 something truly momentous occurred. An object from the heavens fell to Prospero, shrouded in flame, landing in the central plaza of Tizca, the City of Light. As the smoke cleared and hesitant Tizcan citizens, convinced it was not the attack long dreaded from outsiders, approached the crater and saw a ruined metal pod. But the pod warranted only a cursory glance for all the attention soon shifted to the copper-skinned boy with a thick red mane for hair standing at the crater's edge. A demigod had arrived to Prospero and the world would never be the same.

The assembled men and women continued to debate before him. They were politicians, scholars, philosophers, scientists, officers of law and military commanders, and they argued what to do with him. At first he had not known their language but after listening to them for several hours he felt confident to converse in their tongue without issue.

"Ladies and gentlemen," he began, voice rough with having never been used. He knew many of them had innate gifts but some did not and he did not want to inadvertently overload their fragile minds with his teelepathy. They were not like him, instead lesser beings. Killing them in an attempt to communicate would be a poor first impression. "I arrived here not to cause harm. I come in peace."

"What are you?" asked an aged woman, deep lines around her eyes and mouth. Many leaned forward at this, curious as to what he was.

"I am the future," he said. It was what his creator had told him at his inception when their minds had linked and they had begun to converse.

Some scoffed at what they presumed to be arrogance but most nodded, seemingly influenced by the charismatic aura emitting from him, the sense of hope and command.

"Where are you from?" a young man asked, donned in the robes of a scholar.

"I was created in the Cradle of Mankind, Sol." Hushed whispers and astonishment erupted after that announcement.

"How did you come to be here?" asked a middle-aged man clothed in a military uniform, leaning forward with fingers interlocked.

The copper-skinned boy remembered panic, desperation, and tried to communicate with the Emperor who had been on Terra at the time, but something had blocked him. Something ancient and malevolent, something divided into four distinct personalities but united in purpose. He had been terrified, though he would never admit that to another. The last thing he remembered before waking up in Prospero's orbit had been he and his nineteen slumbering brethren being snatched and discarded into the warp's raw tides. But he did not say that, for they would have been afraid and fear led to mistrust and unfounded anger.

"How I came to be here is a mystery to me."

Silence responded to him as the assembled Tizcan leadership shared sideways glances but they did not comment on it.

"What should we call you?"

"Magnus," he said, remembering the name his father had given to him during their first mind-link. "My name is Magnus."

The primarch announced himself as Magnus, gaining the cognomen 'the Red' within days by the Prosperines due to his physical characteristics. Magnus revealed to his tutors of his powerful psyker abilities, much to their delight and relief that the primarch was like them and therefore nothing to fear. While most of his brethren rose to prominence in their respective societies through martial means, Magnus devoted himself to learning, spending days within libraries and voraciously studying, and reading carefully preserved half-faded tomes and parchments to further his insight and understanding of matters. Within months he reached and then surpassed the City of Light's scholar elite. In less than a year, the primarch had graduated with top honours and accolades from Tizca's acclaimed universities. But what set in stone the primarch's psychic mastery was a ritual that not only drew power from the Great Ocean, as all Prosperine psykers had done since time immemorial, but astral projected himself into the warp directly to more closely analyse the Empyrean. This ground-breaking achievement elevated Magnus to the prestigious and esteemed rank of Premier Master Scholar of Tizca, elected by the assembly that had welcomed him a year previous. Though many eagerly awaited what treatises and breakthroughs he would make, Magnus surprised all by saying he would leave the City of Light and explore Prospero to discover what had been sadly forgotten and reclaim what had been tragically lost.

The primarch departed with much fanfare though there was an air of sorrow as most believed Magnus would die in the wastes, that the psychneuein or other hazards would overcome the primarch despite his unrivalled psychic powers and physical strength, his corpse joining countless others littering the land. Yet Magnus departed without fear, excited for whatever awaited him.

The dry wind blew sand into his eyes. Instead of raising a telekine shield, he allowed it to hit him, feeling the sensation of being in the midst of a sandstorm. Learning was not always comfortable or painless; some discomfort was a small price to pay. Magnus covered his mouth with the hem of a dun coloured robe as he progressed, trudging through the shifting dunes with unparalleled ease. As he ascended a dune, he looked out over the desert expanse, his true eyes and mind's eye seeing through the sandstorm with no issue.

Beautiful, he thought. What wonders are buried out there? What secrets waiting to be discovered? What glories forgotten?

Hours passed and the storm moved on, the sky returning to its striking pale blue while the sun blazed down onto the ground. The heat was great but a physiology such as his endured it without cause for alarm. Soon enough he saw a city outline in the distance and made way towards it. Shimmering heat waves distorted the skyline but he could see that it was long decayed, buildings crumbling and half buried by sand. Now with a destination in mind, he created and slipped into a warp rift, feeling the familiar icy chill as he arrived in that realm once more. As he took a few steps forward, Magnus couldn't ignore the feeling that a million eyes were watching him, waiting for something, but before the sensation grew too uncomfortable he exited the rift, arriving in the city centre.

Opening his senses he felt the residual psychic imprint of pain suffered by the city's denizens so long ago, their cries for help as aetheric eggs hatched in their brains, soon to be consumed by xenos young. There was so much pain, so much chaos. His eyes closed as he felt their suffering. He felt it, catalogued it internally for remembrance and opened his eyes as a buzzing sound approached. All around him the buzzing increased and within a minute the whole city vibrated with noise.

He knew what was causing it. The psychneuein soon revealed themselves, rising from dilapidated buildings, hovering in air as they approached, their half-seen tendrils flicking as they trailed behind, warp-energy dripping off them like water. They were ugly, in more ways than physical. They were the embodiment of evil, that which attempted to wipe out humanity on Prospero… and at that they failed.

Magnus ascended through the Enumerations Amon had taught him, and as he rose through them he drew more and more power from the warp. The Great Ocean flooded his veins with power and the temptation to draw more was there but he repressed it as he had been trained. To draw too deeply in an uncontrolled environment was dangerous. And, he privately admitted to himself, he was still relatively young in experience and therefore should not risk it. Not yet at least. There would always be time to draw more, better to do so in a more controlled setting. For now he would seek vengeance for the fallen.

The psychneuein neared him, blackening the sky with their number. The air was abuzz, the air having gone thick with warp-matter.

"I bring the light," he spoke aloud, fist raised and glowing with eldritch fire. "I am the light." Magnus released the power, sending it out in a powerful shockwave that ruptured the psychneuein, splattering xenos gore onto the ground and buildings. Tens of thousands of the parasites died within seconds, the entire city cleansed. Magnus was unsteady, body shivering from releasing so much energy so suddenly, but he quickly recovered. It wouldn't bring any of the murdered denizens back, but it gave Magnus solace that they were now finally avenged.

Choosing a road at random, Magnus made his way down it, searching through the buildings, eager to uncover what had been hidden.

The primarch roamed Prospero for years, travelling to the separate enclave-cities, learning their histories, sorcerous rituals, and more, as well as escorting caravans between cities, reigniting commerce and communication that had been near-impossible and seen as foolhardy before. Magnus' mere presence instilled hope in the people that the entire planet would once again be theirs, especially once the primarch recounted the cleansing of an entire psychneuein-infested city and brought witnesses to see the truth of the matter. After visiting all of Prospero's enclave-cities the primarch returned to Tizca, filled with new knowledge and driven by an innate purpose.

"You, my friend, are a fool," Amon said calmly, walking alongside the towering demigod. Overhead birds cawed and flew in circles, searching for food. Vultures waiting to pillage below.

Magnus chuckled at Amon's words. It had been near a decade since he had left Tizca and while those years had no effect on Magnus, they had greatly affected his mentor and friend. His hair had grown thinner and greyer, while the psy-staff, used to channel aetheric power, was now doubly used as a walking stick. Even tapping into the Great Ocean to extend one's life, something Magnus had discovered in Ythow, could only do so much. Magnus knew the Emperor was close yet still several years away. The empire his father informed him about was rich in medicine and technology, both of which could further extend Amon's life. He just had to hold on…

"I would not say a fool," Magnus finally said as they walked atop Tizca's battlements. More imposing and effective weapons were added, new hieroglyphics imbued with the Great Ocean's power carved into the stone, and the kineshield over the City of Light had been made more firm and even enlarged several more leagues into the wastelands. Already farmers were readying the new lands for irrigation and to become fields of fruits and vegetables one day, pastures for beasts of burden to graze, with a new defence wall being constructed via cranes and telekinesis to protect this expanded territory. "But ambitious, yes, I am that."

Amon grunted agreement. They walked along in a moment of silence, the sound and smell of the sea reminding Magnus of his early youth when he had studied marine biology. Such a learning environment was peaceful, a most tranquil experience.

"To unite Prospero… that is a dream few have had. Not since Antaupaweh the Daring has anyone attempted that." Amon sounded worried.

"Do you think I will fail?" Magnus asked, genuinely curious.

"Antaupaweh was king of three cities, an administrator without peer and a competent general, yet it was his ambition that saw him fail. He attempted what you intend to do, yet his failure and defeat at Seddav Heights by the Ghaoll Confederation led to two cities being destroyed, overrun by his enemies and then the psychneuein. Nearly seven million died. I feel, Magnus that you will undoubtedly succeed, yet that victory will be but the rise before the inevitable fall."

"You fear I will bring ruin not only to Tizca but Prospero entire?"

"Yes," Amon said in a pained voice, "I do. You are human, my friend, no matter how different or superior you are. We are imperfect creatures, blinded by wanting ever more and ignoring our own faults."

Magnus thought on it for a moment before responding. "There is a chance, yes, that I will fail or that my victory will sow the seeds of my destruction, but I am not Antaupaweh nor any that preceded or followed him. I am Magnus the Red and I do not fail."

Amon stopped and looked at him, dark brown eyes searching his own. "And that is why I am afraid."

Magnus swayed Tizca's leaders that the time had finally come to unite Prospero, remaking the world as it had been in long ago. First Tizca's defences were improved and expanded upon, and all of what the primarch had learned in his travels was written down for posterity. Once the City of Light was made more secure, Magnus led the Tizcan armies into the wastelands, establishing outposts and cleansing dead cities of xenos parasites, repopulating them with brave settlers. But that was not all that resisted Magnus. Several cities, led by demagogues fearful of losing power to Magnus, defied the primarch. Though protected by strong walls and even stronger sorcery, Magnus defeated those that denied the future he sought to bring and brought them into his fold. After the Prosperine cities had been united, Magnus was raised by the people and their governing assemblies to be their eternal monarch to guide and usher in a golden age of prosperity and advancement, bequeathing the rank and title of Crimson King to the demigod psyker.

Though the psychneuein population was greatly reduced as a result of Magnus' campaigns to unite Prospero, they remained a significant threat that continuously attacked outposts and newly inhabited cities. The Crimson King, intent on wiping out this menace once and for all, assembled the greatest army Prospero had ever seen, and marched them to the Naun Abyss, the origin of the psychneuein and where their largest nests were concentrated.

The Battle of Naun waged for days, the Prosperines using a myriad of conventional weapons and psyker abilities to combat the parasites. Yet despite their firepower and leadership, the Prosperines were hard pressed, vastly outnumbered, and nearly overwhelmed. Magnus, knowing that a defeat would destabilise his new-born kingdom, teleported himself deep into the Abyss, intent on eliminating the psychneuein queens and securing victory from the jaws of defeat. It was there the Crimson King used both martial might and psychic prowess to defeat the psychneuein queens and eradicated a majority of the xenos population, scattering the rest to rove Prospero until its last days.

With Prospero's humanity united once more, the xenos broken and scattered, many wondered at the age to come and what wonders the primarch would herald. Magnus returned to Tizca and from there directed the world's reconstruction. While he oversaw Prospero's budding golden age, Magnus detected something approaching his homeworld, something familiar. Soon after, the heavens filled with golden light and hundreds of warships appeared in Tizca's night sky. At first there was panic, many believing that with the warp having calmed for decades that a fleet had finally come to do the world harm but in this they were wrong. Magnus assuaged his people that this fleet brought not destruction but a glorious new era.

A single dropship descended from the great warship hovering over Tizca. Its kilometres long flanks bristled with various forms of weapons. Gothic spires protruded from its metal spine, statues of heroes, generals and simple soldiers, from lowly mortals to hulking armoured warriors. It was a wondrous design, filled with awe, intimidation and a promise of a better tomorrow. The warship's name was whispered to him by the minds of those who crewed it.

Bucephelus. The chariot of an explorer, a conqueror, a unifier… an emperor.

The dropship landed in the heart of Occullum Square on a pre-designated zone, built a year ago for this very occasion. It was golden in colour, thunderbolts and eagles adorning it with beautiful intricacy. Its ramp lowered and majestic light spilled forth from the interior, bathing the assembled crowd with its light. Many fell to their knees in adoration, tears spilling from their eyes. A lone figure emerged from the dropship. His skin was Anatolian brown, eyes ever changing, figure strong and proud, and hair a raven's black and falling past broad shoulders armoured in one of the most advanced suits of war-plate Mankind had ever devised.

"Magnus," his father had said, voice deep and powerful, wise and sorrowed all in one. It was the voice he had expected to hear.

"Father," Magnus the Red, Crimson King of Prospero, said as he knelt onto the ground. "It has been a long time."

Magnus swore allegiance to the Emperor upon His arrival, greeting his creator with a familiarity that bespoke of a long established relationship. The Master of Mankind spent some time on Prospero, learning of all His son had accomplished. Father and son then travelled to Terra and it was there the Fifteenth Primarch met his Legion and of what afflicted them. The flesh-change had spread rapidly among the XV, leaving barely a thousand Astartes left by the time Magnus was united with them. The Emperor, unable to devote the necessary time and resources to correct their genetic flaw due to overseeing the Great Crusade's prosecution, allowed Magnus to study the flaw and attempt to correct the flesh-change and save the XV. It was a challenge the primarch tackled head-on, unwilling to see his bloodline die so ignoble a death.

---

Great Crusade-

When the Legiones Astartes were founded during the Unification Wars latter years, the Fifteenth Legion recruited heavily from the Achaemenid Empire, one of the first Terran nation-states to swear loyalty to the Emperor and one of only a handful to do so without bloodshed. Promising male Achaemenid youths were recruited and implanted with the gene-seed of the Fifteenth Primarch.

Like many of their cousins, the XV partook in the Unification Wars final campaigns, waged across Terra's ravaged surface and then participated in the conquests of the Solar System. When the first Expeditionary Fleets left Sol to carry the Emperor's dream to the wider galaxy, the XV were among the vanguard, eager to spread the Imperial Truth to a galaxy shrouded in darkness. Considered tenacious and dependable, though lacking any specialty as what was already developing within the VIII and Luna Wolves, the XV nonetheless brought a fair amount of worlds to compliance in the Crusade's first years. By the Crusade's fifth year psychic abilities began to manifest in many of the Legion's warriors, much to their delight. This soon changed, however, following the Compliance of Bezant.

Bezant was a world inhabited by sun-worshipping barbarians. Typically such humans would have surrendered to the Imperium's might within hours, yet the primitive tribesmen fielded powerful warlocks, allowing them to resist the XV. The XV and the Bezanti warlocks engaged in battle for days, destabilising the planet with destructive warp-energies being cast about by both sides. At the height of the conflict, a psyker warrior of the XV succumbed to what became the first known incident of the flesh-change. The Astartes, Darleth, was stasis-interred in the hope of eventual recovery and it was hoped to be an isolated occurrence. This proved false as over the following years dozens, then scores, and finally hundreds of the XV fell to the genetic flaw's clutches, their physiology becoming unstable. So many fell to the flesh-change that the Legion begun to dwindle, with combat losses further shrinking the Legion.

With the Crusade ongoing and continuously growing in scale and intensity, there were whispers amongst Imperium's upper echelons that the faltering XV should be disbanded, its gene-seed stasis-locked, its armaments and fleet assets assigned to other Space Marine Legions. But this line of thought suddenly ceased upon Magnus the Red's discovery. The Crimson King devoted all his efforts into discovering a cure for the flaw. The search took decades, taking the full attention of the primarch and his Legion whom he renamed the Thousand Sons in honour of their tireless fortitude.

During this time the Thousand Sons brought very few worlds into the Imperium, almost exclusively through peaceful diplomacy, and were effectively semi-retired from the Crusade lest they risk being made extinct. Magnus traversed the galaxy, scouring for anything to stabilise his sons' gene-seed. Countless formulae were created, all failing, even psyker-based attempts proving unsuccessful at correcting XV gene-seed. As the number of his sons dwindled, Magnus became increasingly desperate, frustrated that his extensive wealth of knowledge proved fruitless in conjuring up a cure. The primarch felt he was failing his sons and as their numbers reached the low hundreds, a despairing Magnus chose to ignore the cautioned warnings and restrictions his teachers and father had given him and peered deep into the Great Ocean, searching until something finally peered back.

Magnus' soul scoured the Immaterium for days, though the primarch later told his favoured son Ahzek Ahriman it had felt like years, and when he emerged he did so with the knowledge to create a cure though it had cost him his right eye, earning the epithet of Cyclops. Despite his personal loss, Magnus deemed the venture a success as his Legion was saved from the flesh-change, the genetic flaw seemingly purged from the surviving Thousand Sons. It took decades more yet but the Thousand Sons were steadily rebuilt, though they would remain by far the smallest of the Legiones Astartes.

With the threat of dying out removed, the Thousand Sons returned to the Great Crusade. While many worlds were brought into the Imperial fold by the XV, a select few were integrated into an alliance between Prospero and these worlds, its mandate to share resources and knowledge, while the Fifteenth Legion would protect the member worlds henceforth. This would be known as the Prosperine Hegemony and it spanned the galaxy, numbering over a score at its height. That was not all the XV accomplished, for in their pursuit of knowledge they established what would be the basis for Library Worlds, something which has endured into the 41st Millennium, albeit with some restrictions and constant overview from the Adeptus Arbites and Holy Inquisition. But possibly the greatest contribution, as well as controversial, to the Imperium was the formation of the Librarius within the Legions. In conjunction with Sanguinius of the Blood Angels and Jaghatai Khan of the White Scars, the Crimson King encouraged the adoption of a Librarius across several Legions.

While applauded by many, some saw the dangers inherent in empowering transhuman warriors with warp-based powers. Several primarchs and their Legions criticised the Librarius, notably Mortarion and Corax, but the most vocal detractor was Leman Russ. This discord between the two originated from the Aghoru Compliance. The planet had accepted the Imperial Truth without issue, welcoming the Thousand Sons with open arms. Aghoru was pre-industrial, largely inconsequential, except for what the locals called 'the Mountain.' What began as an archaeological survey devolved into fierce combat between the Thousand Sons and the entombed psychic Daeisthai spirit-warriors, inadvertently awoken by a XV foray.

Magnus' intent of preserving the Mountain's tombs by purging the xenos threat was foiled by a recently arrived contingent of Space Wolves who felt the rampant use of psyker powers was dangerous and unwise, creating a bridge between real-space and 'Hel.' The Wolves of Fenris gave the Crimson King an ultimatum to depart Aghoru lest they risk destruction. The Fifteenth Primarch was enraged at the threat but did not wish to risk open conflict between the two Legions, departing the world moments before the sons of Russ fired. Emergency evacuation was carried out by the Thousand Sons to rescue as much of Aghoru's population as they could but only a fraction was saved before nuclear winter set in. Many were saved but millions more died and the already tense relationship between the VI and XV soured, both swearing to avoid fighting alongside the other.

This aversion of each other lasted for decades until the Ark Reach Cluster Campaign. The Emperor ordered the Word Bearers, Space Wolves and Thousand Sons to conquer the cluster. At first things proceeded well, most of the cluster falling rapidly to the Imperium. But as the three Legions reached the capital of the Avenian Empire, Ark Reach Secundus, known to the inhabitants as Heliosa, it took the Imperials nearly six months to secure compliance, the enemy's tenacity impressing the Astartes and primarchs. Yet it was in the final days of battle, as the last tower-city of the Avenians was besieged, that the sour relationship between the VI and XV devolved into outright hostility.

Captain Aethor Raza stormed through the hastily erected barricade with mind and body. His khopesh power sword cut through Avenian armour and flesh with ease, their corpses littering the ground while more legionnaires pushed through the gap, entering the tower-city's lower levels. His mind tapped into the Great Ocean, drawing power from its depths and unleashed it as lightning against an emplacement of troops. The smell of cooked flesh entered his helmet despite active air scrubbers.

A heavy stubber fired at the Astartes, raised on a perch. Raza raised an outstretched arm before it was swatted down by a legionnaire clad in blue-grey Mk. II war-plate. Raza sneered and the Wolf snarled.

"Cease your maleficarum, sorcerer," the Fenrisian barked in heavily accented Low Gothic. Nearby a krak-tipped rocket slammed into the stubber nest, killing the defenders. Raza saw a Rune Priest wade through the battle, eldritch power flaring from his staff, bone charms and fetishes dangling from his person. There were scores of Wolves compared to only a handful of Thousand Sons.

"Hypocrites," he muttered darkly, bile building in the back of his throat in disgust. He would have done something more but he stilled himself, calming his emotions by going through the Enumerations to find inner peace. Magnus had warned his sons to ignore Fenrisian brashness. Complaints made by the XV to the Emperor in the aftermath of Aghoru had gone unnoticed. Therefore, the Crimson King wished to conduct this campaign in a timely order then depart without relations deteriorating further.

Raza opened his mind to pulse-order his brothers onward but something stopped him. It was something old, incredibly old, intelligence infused with malicious intent. Before he could ponder it more, a sudden flow of the warp entered his veins unwittingly. He cried out for help, the cry becoming an unnatural scream, giving pause to his brothers and cousins who stopped in their tracts to look at him, the breach into the tower-city temporarily forgotten. Raza fell to the ground, appearing to kneel, body shaking as Immaterial energy flooded through him. His genetic code began wavering, the gifts of his primogenitor turning against him, he felt his skin move, growths coming forth, piercing through flesh and armour. The curse of the Legion, thought defeated, had returned and it was at that moment he felt true panic.

He opened his mouth to warn the others but a roar came out instead, a monstrous bellow that was not natural to the universe. As his mind shut down and the flesh-change took over, he saw the concern of his battle-brothers as well as the disgust the Wolves had for him.

Magnus felt the anguish and horror of those afflicted by the flesh-change. He rushed to his sons but upon arrival found a slaughterhouse. Several of his legionnaires lay dead alongside the corpses of dozens of Wolves, while a gore-drenched Leman Russ stood over the Prosperine corpses. Magnus was infuriated and nearly lashed out at his brother if not for the timely intervention of Lorgar. The Urizen convinced both parties to depart the planet without further violence, which soon became known as Shrike in Imperial records due to the avian beasts the Avenians employed in battle.

Not long after the Compliance of Shrike, a majority of the primarchs were called to attend the Emperor on Ullanor to celebrate the Imperium's great victory secured there. Magnus rushed to Ullanor, intent on lodging a complaint against Russ in person. Yet at the Triumph, the primarch was unable to discuss matters privately with his father as other matter took precedence, namely Horus' declaration as Warmaster.

Magnus left Ullanor frustrated but strived to move on from recent events, dedicated to bringing the glorious age of enlightenment promised to Mankind after the Great Crusade was accomplished. The primarch also wished to analyse how the flesh-change had returned, no matter it being an isolated incident. It was worrisome to the Crimson King that the flaw had returned and he intended to discover the truth of the matter and correct it. Then came the Nikaea summons and everything changed.

---

Trial of Magnus the Red-

Psykers had long been a matter of debate within the fledging Imperium. Some, fearing a return to the horrors of Old Night, argued that the psyker population should be severely curtailed and controlled. Others believed that humanity should be allowed to evolve naturally without such control over its evolution. The pros and cons had been debated for two centuries but with the Emperor soon to return to Terra the issue needed to be resolved at once. The Master of Mankind called for a conclave to take place on Nikaea. Magnus and his inner circle journeyed to Nikaea, determined to defend their point-of-view.

During the Council of Nikaea, Magnus argued passionately and boldly yet his critics, particularly Russ and Corax not only pointed out the dangers of psykers and the threat they posed but also the Thousand Sons research into esoteric fields of study, some that were frowned upon by the Emperor, particularly the study of dangerous xenos artefacts and more specifically the Empyrean. While Magnus and his sons saw the warp as a well of boundless knowledge and potential, many saw it as a source of damnation and corruption. While both argued their sides vehemently, it was a group of Librarians from several Legions that had the greatest effect.

The Librarians argued that psykers, while dangerous, were too great a weapon, something that if the Imperium did not employ would hinder their offensive and defensive potential. The Librarians proposed that psykers, even their transhuman practitioners, be placed under more oversight with stringent restrictions on what they could research and wield into battle. This proposal would allow the Imperium to reap the benefits of having psykers in its armed forces whilst simultaneously negating much of their threatening potential, controlling it in a more supervised and centralised environment. The Emperor agreed and thus the Librarian Compromise was born. What should have been a victory for the Crimson King turned to ash as the Emperor nonetheless censored the XV for rash pursuit of forbidden knowledge and the widespread use of psychic powers to a degree that many deemed wanton sorcery.

Magnus felt betrayed by his father, calling Him a hypocrite seconds after the judgment over the matter had been delivered. The Compromise and Edict were a sham in the primarch's eye, meant to capitalise on the work he and the Thousand Sons had tirelessly carried out for over a century, their legacy and reputation tarnished by Imperial censure. While the Emperor returned to Terra, intent on carrying out His Great Work, the Warmaster led the Imperium's armies towards the Great Crusade's inevitable conclusion, and the Sorcerer-King fled to Prospero, ashamed and embittered.

Magnus recalled much of his Legion to Prospero. Officially it was to more efficiently and more rapidly integrate the Edict, to reform the psyker-scholars of the XV into what the Compromise envisioned. On the surface, this appeared to be true as the Legion adopted new policies following Imperial law, as well as halting study in a host of fields, particularly that concerning the Great Ocean. The truth of the matter however was a stark contrast to the feigned obedience. Magnus worked hard studying the Immaterium, accepting risks that once would have been unwise to undertake, believing that if something of significant magnitude was discovered his father would be forced to rescind the Nikaean Edict and allow unrestricted research to continue once more, which would subsequently restore and even bolster the Fifteenth Legion's reputation.

Years passed as Horus led the Imperium ever closer to total galactic domination, and the Cyclops was no closer to making a breakthrough. Yet in his search for answers, Magnus uncovered the greatest of treasons, one initiating inside the primarch brotherhood itself.

"It can't be," Ahzek Ahriman said, too stunned to say more. The First Captain and Chief Librarian stood rigid in his primogenitor's private chambers, shocked and appalled by the horror the Crimson King had told him. His mind delved countless paths, searching for a way out of it, but the knowledge of the war to come had changed all futures that he could foresee. All he saw was misery, death and endless war.

Magnus could feel the tormented emotions of his favoured son and it tore at him.

"I am sorry, Ahzek. I should have foreseen this. I should have known."

"How could you have known?" Ahriman asked, voice distant with thought. "How could any of us have known? Over two centuries of brotherhood and Unity broken at the seams. To think it would be Fulgrim, he who adores the Emperor above most."

"Adoration can easily lead to darker paths; one my brother has stumbled upon, guided by outside forces."

"Outside forces? Such as?"

"I'm not sure, I did not sense them directly, but all I know is that the Imperium is about to be ripped in two and that Fulgrim and Lorgar are the instigators." Magnus closed his eye, the vision he saw showed him what Lorgar would become and what he already was, hiding beneath the surface. A single tear rolled down his cheek and fell to the floor. Mind weighed by the vision's severity, the Sorcerer-King glanced at the thousands of tomes stored high in his inner sanctum. He had read of devastating civil wars, great rebellions, and fratricidal betrayal within their binds but nothing could prepare him for what was coming. The Empyrean held many secrets, many prophecies, and searching for them had led to deeper and darker things.

"We have to warn the Emperor," Ahriman said suddenly, certainty clinging to his aura.

"There is no time, my son," Magnus said resignedly, "Astropathic communication would take too long and leave room for misinterpretation, while traveling to Terra could take months, if not longer due to how dangerous warp travel has become of late."

"Then it is hopeless," Ahriman stated, "War will come and the Throne will be at a disadvantage. The traitors would tear through the Imperium… billions would die."

"Trillions," Magnus spoke quietly. A thought struck him. "The situation is not as hopeless as it seems," the primarch rose, enthusiasm flooding through him at the daring idea. "There is a way to warn my father."

Ahriman eyed him curiously, asking after a brief hesitation. "How?"

In his desire to warn the Master of Mankind, Magnus defied His Edict. Using forbidden sorcery, the Sorcerer-King sent an astral projection into the Great Ocean, coursing through its deadly depths to reach the Emperor. But just outside the Emperor's laboratories beneath the Imperial Palace, Magnus found himself unable to reach his father. Desperate, the primarch made a pact with a warp-being of formidable power, later revealed to be Tzeentch. Empowered, Magnus' soul broke through the psychic barrier and as a result damned the Fifteenth Primarch and his sons for eternity.

Magnus' intrusion crippled the Emperor's Webway Project, opening a tear from Chaos-corrupted Webway tunnels into the Imperial-controlled sections. The incidental psychic onslaught Magnus created saw to millions dying on the Throneworld, with millions more suffering dreams of a demigod surrounded by flames and horror. This led to the rise of Chaos cults on Terra, which were only put down by the extreme lethality of the Death Guard and Silent Sisterhood.

The primarch, horrified by what he had done, fled back to his physical form in Prospero's Reflecting Caves. There, he told the Rehati that he had failed and that the XV would be perceived as traitors to the Imperium. Soon enough this was proved true when the Space Wolves entered the star system and headed directly towards Prospero arrayed in battle-formations.

The VI, charged by the Emperor to arrest Magnus the Red, had their orders changed prior to their arrival to Prospero. The orders, manipulated by the traitors to sow dissent amongst Emperor-loyalists, became a sanctioned extermination, something the VI had done before. As the Space Wolf war-fleet neared Prospero, Magnus ordered his sons to defend their homeworld.

The Burning of Prospero was a short but brutal affair, heavy casualties suffered on both sides. The extensive orbital defence grid and Fifteenth Legion war-fleet fought desperately to save their homeworld but the Thousand Sons and their auxiliaries were outnumbered and outgunned. The XV fleet was pushed back, allowing Russ to bombard Prospero. The major cities of the Astartes homeworld became radioactive ruins, destroyed by the unforgiving and unrelenting VI. The only major city to endure the assault was Tizca, the City of Light protected by the Raptora Cult via powerful kine-shields, but many of the Cult died to protect the city, their powers consuming them as they pushed themselves too far in maintaining the kine-shields.

Realising that successful bombardment could take days, Russ ordered his sons to land and assault the city directly, to conquer it street by street, cleansing it of witchkind and leaving none alive. The VI did so thoroughly. After establishing air supremacy over Tizca, tens of thousands of Space Wolves descended in drop-pods and dropships. The Thousand Sons were caught off guard, with the only Prosperine forces near the VI landing zones being Spireguard regiments. Though they reacted quickly and fought bravely, these mortals were defeated and cut down within minutes by the Fenrisian savages. The VI advanced into the city, encountering stiffer and stiffer resistance the closer they neared the Legion's pyramids.

Magnus masterfully directed the city's defences, but he was no match for his brother's brutality and barbaric sons. Even the Thousand Sons' greatest weapon, their psyker abilities, was crippled by the hundreds of Silent Sisters that accompanied the Wolf King and his get onto the battlefield, despatched by the Emperor. Another fact the XV interpreted as being declared traitor by the Imperium. The situation became so dire for the Prosperine defenders that the stasis-interred legionnaires afflicted by the flesh-change before Magnus had halted it, were awoken and unleashed against the Space Wolves. These Astartes were grossly mutated and malformed, yet many had great strength, endurance and speed, and caused the deaths of hundreds of Wolves that otherwise would have lived. Yet not even this desperate measure could stave off the inevitable.

Amidst the ruins of his great pyramid Magnus fought the Wolf King, lupine savagery versus sorrowful defiance. As the two fought, Magnus realised he would lose to Russ. Any such defeat would deal a crippling blow to the defenders' morale and lead to their utter annihilation. Therefore, Magnus ordered his Legion to break through the Executioner's fleet and flee into the warp. Most lamented the order, while some even chose to ignore it, but a vast majority of the Legion saw the necessity and thus the XV marshalled all forces it could and attempted to evacuate, boarding their scattered fleet and fleeing with little to no coordination, suffering irreplaceable losses as they abandoned Prospero. While many of his sons saved themselves, Magnus attempted to flee via a warp rift but became cornered by Russ and a squad of Silent Sisters on the steps of the Pyramid of Photep. While he was able to slay the pariahs, the Cyclops found himself at the mercy of Russ who did not hesitate to wound him, breaking Magnus' spine upon his knee for all to see. The Wolf King towered over the crippled Sorcerer-King but before the killing blow could be delivered, a Thousand Son officer interjected himself before the Lord of Winter and War.

Every breath brought pain. The sound of war was muffled, his skin aflame as his body tried to heal itself. Though his vision was clouded, he could see his brother clearly. The Wolf King was dressed as a barbarian warlord, wolf skins and bone fetishes adorning his armour, honey blond hair braided and falling past his shoulders. Russ' cheeks were like mountain sides, eyes the colour of chipped ice, and snarling teeth reminiscent of the great wolves prowling nearby. The energised frostblade was raised as Russ neared, yet despite the hate and determination present in body language and facial expressions, Magnus would have sworn Russ' eyes held regret.

Magnus glanced at the blade, then looked at Russ. His powers flickered, just beneath the surface, returning in a trickle but delayed due to his injuries. But as the sword fell to deliver the killing blow it was stopped in mid-air. Magnus could see the aetheric energy holding it in place. Russ cursed but the blade only marginally moved as more strength was applied.

+Father,+ came a familiar voice.

+Phosis, my son, what are you doing?+

+Saving the Legion+ the Thousand Son Captain replied. From Photep's innards emerged Phosis T'Kar, Captain of the Second Fellowship and Magister Templi of the Raptora Cult. Warp energy crackled over crimson armour like lightning, his helm's eyes alight with power. Magnus' warp-sight could see his son drawing much from the Great Ocean. Too much, in fact.

+You'll die,+ he sent, +your body can only take so much.+

+My life is of little consequence, but yours… yours matters more than any of us. From you the Legion can be rebuilt, from you the Imperium can learn the error of its ways; from you we can be redeemed. Now save as many as you can. Live to fight another day.+ And with that, T'Kar rushed Russ, weapons charged and primed.

Russ had been surprised by the psychic attack but a primarch did not need pariahs to protect them, they had innate abilities no matter what Russ and others proclaimed. The Sixth Son overpowered the sorcery laid against him and turned to face the legionnaire. Magnus' body was healing rapidly, though the broken spine would take some hours to fully heal. Yet his connection to the Great Ocean was no longer constricted and power flooded into him. For a moment, he almost joined T'Kar in fighting Russ but there was no guarantee that a weakened primarch and an Astartes could overcome a primarch who had been crafted to be the Emperor's Executioner. If he stayed, he may fail and that failure would spell the end of the XV.

Casting his mind over the City of Light he could feel thousands of his sons still fighting, desperately holding back the Space Wolf assault but that defiance was crumbling as positions were overrun and more of the VI landed, further increasing the size discrepancy between the two Legions. Magnus concentrated, muttering a spell he had long worked on, fearing the time he would ever be forced to use it for if it failed it would be a disaster, yet he had no choice now.

With the final incantation, he felt the wind stir as hundreds then thousands of small tears into the Empyrean opened, allowing the surviving Thousand Sons on-world to escape. As the pull of the Great Ocean lifted him to the tear above, Magnus watched Russ grab T'Kar to prevent his escape. The Wolf King looked at Magnus' rising form, snarled and violently snapped T'Kar neck, the ceramite and plasteel buckling easily under Russ' strength. Magnus felt a tear slid down his cheek before the cold embrace of the warp enveloped him.

The valiant sacrifice of Phosis T'Kar bought enough time for Magnus to orchestrate the withdrawal of the thousands of his sons who remained, either willingly or unable to get to a dropship in time, and transported them via sorcery into the XV fleet that soon entered the warp via several Mandeville points. While the Wolves finished their razing of Prospero, the Fifteenth Legion scattered across the galaxy, guided only by Magnus' will.

---

Fulgrimian Heresy-

Magnus knew that Russ would hunt him down, like a wolf stalking wounded prey, and created a bold plan in conjunction with Ahriman to throw Russ off the scent. Despatching the flagship Photep to the Akkad System, Magnus bonded a majority of his soul to a greater daemon, making it compliant long enough for Russ and the Wolves to hunt down the flagship, using their Rune Priests own talents against them as they had been tracking Magnus via his blood coating Mjalnar's blade and were drawn to the soul-majority aboard the Photep.

The plan worked, though a not insignificant amount of the ever diminishing Thousand Son fleet was destroyed, including the Legion flagship, and the loss of the Prosperine Hegemony's most important Library World. Despite these irreplaceable losses, Magnus contented himself that the VI was too far out of position to seriously hamper the War Commander's main offensives. Though Magnus would detest what Fulgrim and Lorgar had done in manipulating the events that led to the Burning, the Crimson King nevertheless showed himself to be a dependable ally to the Arch-Traitor. Many battles were won by the traitors due to the direct intervention of the Cyclops and his legionnaires.

A third of the Thousand Sons survived Prospero. Already the smallest Legion by far even before the Burning, the XV nonetheless willingly fought beside the other Traitor Legions, set on righting perceived wrongs. Across a war-torn Imperium, the psykers of Prospero left behind a trail of blood in their wake as they sought to end the Emperor's reign. Untold billions died as a result of Thousand Son sorcerers, forever tainting their once proud and noble name. But to Magnus, the ends had come to justify the means. If the XV was to be restored to their rightful place and the Edict rescinded then the Emperor must die and be replaced by the Phoenician. It was a painful realisation but one the Prosperine Primarch came to embrace. For seven years, Magnus fought alongside the War Commander, acting as an advisor and a general. Though other Traitor Primarchs, such as Angron and Ferrus Manus, did more to advance the rebellion to its end goal, the contributions of Magnus the Red cannot be denied.

When the Eight Legions finally invaded the Sol System, it was Magnus who covered the star system with a psychic veil, blocking any astropathic communication from the besieged Imperials to any nearby forces that may have been able to help. This proved crucial to Fulgrim's plans as it allowed him to overrun the Imperial Palace bit by bit for months without concern of impending loyalist reinforcement. While it did not prevent the Raven Guard from arriving to Sol and reinforcing Terra, the XIX having already been en route to Terra prior to the Siege, it did prevent the other Loyalist Legions from communicating and coordinating with the Throneworld, delaying any kind of retaliatory response.

The traitors' advance was halted at the Eternity Gate with the banishment of Ka'Bandha by Horus. The situation became desperate as Magnus informed the Arch-Traitor of inbound loyalists and the furious War Commander came up with a bold plan to win the war. On the ninety-fifth day of the Siege, the Inner Palace's void-shields were sabotaged and the Phoenician led a strike force to the Throne Room. The fortunes of the rebellion depended on this last effort. It failed. The Arch-Traitor was killed and as the Sons of Fulgrim retreated in despaired shame. The Thousand Sons withdrew as well, teleporting themselves aboard their vessels just prior to fleeing into the warp.

Magnus, who had pinned all his hopes and ambitions on the war's outcome, became melancholic and fell into a deep depression. The XV, bereft of their gene-sire's leadership, fragmented and scattered across the galaxy. Some fled to the surviving worlds of the Prosperine Hegemony to rule as their own private fiefs, while others formed warbands that roamed the Imperium, raiding for resources and plundering for knowledge. A majority, however, journeyed to the Eye of Terror, following their primogenitor to the Daemon World of Sortiarius.

On the Planet of the Sorcerers, Magnus was raised to daemonhood by Tzeentch. The Sorcerer-King isolated himself in the Tower of the Cyclops, searching the Great Ocean for answers. It was during this time that the flesh-change returned, rapidly spreading through the Legion's ranks. Desperate pleas to the primarch fell on deaf ears as the Crimson King was more interested in matters of the aether rather than that of the flesh. Though he did order his sons to find a way to save the Legion, the Daemon Primarch did little in the way of direct help.

---

Sins of the Father-

+Father, please,+ Ahriman pleaded, standing in the primarch's library, tomes floating in the air, appearing and disappearing at a whim, +help us.+

+Why do you need my help?+ Magnus said distractedly, the demigod's sole eye scanning dozens of tomes hovering near his person. It had been months since Ahriman had spoken to the Sorcerer-King while most of the Legion had not even seen their father in years. Not since Terra… not since the failed Siege.

+The Legion is nearing extinction. Soon your bloodline will end, our legacy naught but failure and overreaching ambition.+

Magnus stopped and turned to stare into Ahriman's soul, causing the First Captain to hesitantly step back. Never before had he been frightened of his father in such a way. +And why should I concern myself with this matter? Why should I involve myself in your fate, a fate the Great Mutator has crafted after millennia of planning. Rejoice, Ahriman, for the Architect of Fate has taken a keen interest in you.+

Ahriman's jaw locked in disgust.

+You are dismissed,+ Magnus said unconcernedly.

Ahriman had turned around and walked towards the entrance before he realised what he was doing, the impulse to follow his primarch's commands still deeply ingrained. Gritting his teeth, he cursed Magnus but above all he cursed the being that pretended to be a god, the creature of damnation that had ensnared his primogenitor.

At the entryway, his father's mind spoke to him again.

+I know of what you plan, of the Rubric you have been creating these last few weeks. Though I will not lend assistance directly, Ahzek, I am not without some fondness for my sons.+ A heavy chained tome fell from the floating library overhead and settled into Ahriman's hand, whispers flooding into his mind as soon as he touched the hieroglyphic-inscribed cover. Ahriman stared at in disbelief.

+It is curious that I still harbour attachment for my progeny. I had thought my ascendance would have erased such things but it appears not. No matter. Think of it as a gift. Learn well, Ahzek, and even if you fail, know that it was what Tzeentch desires and that we must follow the path laid before us… no matter the cost.+

Ahriman glanced once more at the Book of Magnus then at his father who was once again immersed in his reading. To have the primarch's own tome of sorcery and knowledge would greatly aid the cabal in successfully enacting the Rubric.

+I will save the Legion, father,+ he said but Magnus did not deign a response. Ahriman bowed his head in thanks and departed, hope stirring in his hearts.

As the flesh-change whittled down the already decimated Thousand Sons, and with their father effectively disinterested in their affairs, several Astartes came forward with proposals to alleviate their ruinous genetic degradation. The most daring, and many would deem it foolhardy, was Ahzek Ahriman's Rubric, an attempt to correct the Legion's gene-seed through the use of a complex and not fully understood sorcerous ritual. Using the Book of Magnus as a guide, Ahriman conducted the Rubric atop a pyramid built specifically for the ritual.

Daemons hissed upon the wind, lost souls in torment wailing like a hurricane, and the angry curses of brothers filled the air. Ahriman spared them a brief glance, seeing them climb the carefully constructed pyramid to prevent the ritual's completion. They were afraid, believing the it would backfire and kill them all. Ahriman understood that fear even if he did not share it. The Rubric would work. It had to work. The primarch's book had resolved many issues and clarified certain procedures, though admittedly not all of them.

Ahriman turned back to the ritual, his gaze looking over those he had convinced to assist. Amon, Hathor Maat, Ctesias, Madox, Tolbek, Raziel, and Setekh, powerful Sorcerers all, they lent their power to his, funnelling energy into the Rubric. As the ritual continued, their disagreeable brothers drawing ever nearer, the Book of Magnus rose into the air from its pedestal, fell-light bleeding from its pages. It rose several metres above them when lightning split the sky of Sortiarius and struck the tome yet leaving it unmarred. Raw warp energy was building, each sorcerer moulding it, refining it for the Rubric. More lightning followed, rapid as an autogun. The air tasted of ozone, burning, and the true Immaterium.

The hieroglyphs alongside the pyramid's flanks sprang alight with warp-fire. Ahriman heard some of his brothers perish before they raised kine-shields about their persons. Their deaths were but another tragedy in a history of misery, weighing upon Ahriman's conscious, but it mattered not. The fate of a few legionnaires was inconsequential compared to the fate of an entire Legion.

"Ahriman," called a familiar voice, filled with disgusted, desperate rage. Iskandar Khayon. "Don't do this! You'll damn us all!"

Ahriman focused on the ritual and spoke the final words in sync with the cabal, a storm of lightning impacting the Book of Magnus, and suddenly everything… stopped as if time itself stood still to witness this moment. Ahriman knew that Tzeentch and the other three stopped their Great Game, if but for a moment, and watched what would be the fate of the Thousand Sons.

Everything snapped back into focus like a thunderclap, power rippling from the Book. As the wave of energy washed over him, Ahriman's body began to burn; his very genetic code at war with itself, the Great Ocean flooded his veins, attempting to make right Magnus' hubris of old. His brothers were screaming in pain, the world locked in a whirlwind of change and devastation, and the last thing he heard before unconsciousness overcame him was the laughter of an uncaring god.

Ahzek Ahriman, First Captain and Chief Librarian of the Fifteenth Legion, had absolved the flesh-change… but at great cost. The Rubric of Ahriman removed the flesh-change from the sons of Magnus, the ritual deemed a success, but the gods are forever cruel as over ninety percent of the Legion suffered an unforeseen side effect. A vast majority of the Thousand Sons had little to no psyker abilities and Ahriman's spell affected them negatively, reducing them to naught but ash within sorcery-sealed armour, trapping the soul inside and violently scattering it to become little more than an automaton in legionnaire form. Thus Rubric Marines came into being, Ahriman's unintended sacrificial pawns. The hundred or so legionnaires that did not become Rubricae were the psykers whose powers were greatly increased by the Rubric, though all lamented that their rise in psychic mastery came at the price of their brethren.

While the Legion found itself dazed and uncertain in the Rubric's aftermath, Magnus descended from his Tower for the first time in years. The primarch was none too pleased that so many of his progeny had turned into hollow suits of warp-cursed armour, but nonetheless thanked Ahriman for saving those that he could. Yet Ahriman could not forgive himself and begged his gene-sire to banish him. A wish Magnus agreed to. Ahriman declared he would not set foot upon Sortiarius until he had discovered a way to resolve the Rubric's flaws. From that day onward Ahriman became known as the Exile and has henceforth travelled the Eye of Terror and beyond, attempting to understand the nature of Tzeentch and through such a pursuit he aims to gain the necessary knowledge to correct the Rubric and redeem himself in the eyes of his father.

With the Legion's extinction prevented, Magnus the Red turned his gaze on the Imperium. It had been two centuries since Fulgrim's Heresy and the Imperium was in the midst of recovering. Feeling the moment was opportune the Crimson King gathered two score of his Sorcerer sons, over five hundred Rubricae, the entirety of the rebuilt Spireguard regiments, and the vast bulk of the Legion's fleet assets. With such a formidable force assembled, the primarch set out towards an Imperial world known as Aginthon VII.

The world of Aginthon VII was a backwater, populated only by a penal mining colony and a small Arbites garrison. The arrival of the Thousand Sons was heralded by haunting dreams among the inmates and lawmen. As the traitors neared the world, planet-wide storms and massive earthquakes began, halting all mining and seeing tens of thousands die, followed by mass riots the Arbites barely were able to contain, much less suppress. By the time Magnus arrived, Aginthon VII was embroiled with disorder.

It is debated by many Imperial scholars why Magnus came to such an out-of-the-way world. Some theorise it was to establish a forward base to launch attacks into nearby star systems that were of far more import, such as Gharran or Ekavon III. Others believe it was to establish a warp storm over the planet to allow the traitors to more swiftly enter real-space directly from the Great Eye. While the truth may never be known, what is known is that nearby psy-listening stations picked up on the damning arrival of a Traitor Primarch into the Imperium and a thousand seers wept blood and dreamed of towering one-eyed daemon lord ripping through the tear of real-space.

The small Aginthonian SDF was swept aside with ease and the Traitor Astartes landed into a swampy mire, far from the planet's penal centres, and it was there they began draining the swamp. The surviving Arbites called for help and help soon arrived in the form of two Adeptus Astartes Chapters. The Iron Warriors and Space Wolves arrived, though not in full force as thousands of Space Marines from both Chapters were elsewhere across the galaxy. This did little to lower loyalist morale as both Chapters were led by their respective primarchs. The Iron King and Wolf King, their dislike for one another infamous, put aside their differences and united to combat the threat the Red Cyclops posed. Knowing his force to be numerically inferior by a significant margin, Magnus opened dozens of warp rifts across Aginthon VII, especially in the mines which would tie down some few hundred loyalist Astartes in their attempt to prevent the daemonic hordes from combining. Tens of thousands of daemons emerged from the Great Ocean, acting as cannon fodder and a barrier of warp-flesh between the Imperials and the Thousand Sons.

As Perturabo and Russ led their sons into battle, carving their way through the daemonic horde towards the Traitor Primarch's position, Magnus excavated a long lost city from the swampy marshland. It was a marvellous city that once featured kilometre long spires of glass, immense coliseums for entertainment and vast museums of learning and study. The xenos race, whose name has long been forgotten, had risen and fallen millennia before the Emperor revealed Himself on Terra. In the lost city's central ziggurat resided an artefact of great power: the Staff of Tomorrow. The Staff was constructed by Kairos Fateweaver in a forgotten age, binding the essences of rival Lords of Change. It is wrought from changefire and dispels prophetic visions from the Well of Eternity. While the Staff is a weapon of great import, whose very name has inspired a thousand cults to form and disperse across time and space, but it is what the Staff bears atop it that Magnus the Red sought. The Tome of Destiny records what both of the Fateweaver's heads proclaim, mixing insights into the shrouded past with visions of possible futures.

As Kairos croaks, new text is inscribed across the pages, morphing and rewriting itself even as time and events unfold. To look upon those unholy pages is to invite madness, but to be struck by the Staff itself is worse, for it is change made manifest. Those blessed by its touch ripple with agonising transmutations. It was for this Tome that Magnus sojourned from the Eye, risking what few resources the XV was still able to field.

Even from the ziggurat's entrance, he could feel the raw power of the Staff pulsating throughout the structure's myriad of corridors and chambers, seeping into the stone and beating with a life of its own. Magnus entered, followed by nine Sorcerers, each followed by nine mutant thralls who shuffled along in their wake, whispering spells and crying corrupted blood.

Magnus led his sons into the depths of the ziggurat. The path was ever changing, the layout shifting with every turn. It seemed the Staff would only accept those wise and clever enough to discover it. Rooms blinked in and out of existence, becoming stone walls or gaping pits. For hours they journeyed, descending into its decrepit depths. Almost all would have been lost and died in the shifting ziggurat, but Magnus was a Daemon Primarch, favoured of a god and therefore the shifting did little to mislead him. Finally they reached a long hallway of mirrors. The mirrors showed things that had been, that were, and what would be, and even things that had not happened… but might have, in another life, another universe. As he passed the mirrors, he could feel his soul being tugged, his essence slipping into the mirror-verses to see. Magnus saw…

-A city held aloft with incalculable psychic might in the attempt to save those desperate innocents, millions of souls crying for salvation as they forcibly returned to the world they sought to escape, a king clad in crimson near-buckling under the strain but attempting to prevail-

-The Lion standing over Curze, mud splattered over them both. The Lion was majestic and unyielding, Curze demented and maniacal. The Lion raised his sword, lightning crackling across the dark sky as it began to fall-

-The Angel Fallen descending with wings spread, bringing death and destruction to his father's empire-

-Perturabo and Dorn playing regicide, easy banter flowing between them over tactics and hopes for Mankind, a golden age nearing ever closer-

-The Raven Lord savagely cutting down the Hydra Lord before the towering Prospering Heights, his fratricide initiating the rebellion so long devised-

-Himself sitting upon the Golden Throne, face stilled with concentration as he kept the Webway open for the Imperium's fleet to traverse the galaxy faster and far safer than the corruptible Immaterium-

-Himself laughing maniacally as he sat in the blood covered archeotech his father had so toiled upon. With but a thought he crumpled the Webway tunnels, inviting in the Dark Gods who had so blessed him with sovereignty over his rebel brothers, thus bringing about the Age of Chaos-

-Guilliman sitting upon his throne, the Octed and Ultima adorning the Armour of Reason, talon-tipped Gauntlets resting on the throne's arms, ready to be used to murder worlds. The Thirteenth Lord radiated fell power but not even the Arch-Traitor could hide the open wound on his chest, eyes reddened by pain, misery, loathing, ambition, and the will to see ten thousand years of war come to the outcome he had so desired-

-Fulgrim standing over a version of himself, beating the other-Magnus with his fists, yelling, "Wake up, Magnus. Wake up! You need to feel. Feel! Anger, base emotions! Feel it, embrace it!" Fulgrim harshly enunciated. "Stop being an empty shell of the brother I used to know. Where is the Crimson King that defied a butcher?! Where is the Crimson King who delayed two Traitor Legions to Terra?! Where is the raw power?!"-

Magnus blocked his sons and their thralls from seeing the mirrors, willing them to see nothing but a twisted reflection of themselves. The knowledge these mirrors carried would cause some to question, to ponder about roads not taken. None could be trusted with such information, only he had the strength and the will to see them for they really were: lessons, the ever-twisting fate, full of chance and manipulation. Was this what Tzeentch saw? Not only the threaded pathways of possibility for this universe but others as well. He would have to study this further upon returning the Sortiarius.

The final two mirrors, on opposite sides, were different. Not in their form, but in what they presented. One showed a white haired youth whom he knew to be Fulgrim. But whispers of that 'verse flowed to him and Magnus knew that was not his name, not there at least. The world he saw was a world without resources, mined out millennia ago, and ruled by savage gangs and desperate scavengers. Faro Aquilar, the mirror seemed to say, First-Found, the Restorer, the Thunderbolt…

The last mirror showed something truly strange. It was a dark chamber, a three storey plexiglass window stretching horizontally across the chamber. The star speckled background revealed it was aboard a warship strategium. In the centre hovered a sole hololith, emitting from several projectors built into a large marble table. It was of Terra, Magnus realised, data streaming, attack vectors and various other statistics appearing and fading, cycling through various battle-plans. Standing before the projection was an imposing figure, unmistakably clad in Legion war-plate scaled to fit a demigod.

He was a primarch, of that there was no doubt. His aura could even be felt through the mirror, as was the caress of Chaos upon his soul, the talons of the Great Four sunk deep into him. The light from the hololith lit up the primarch's face, giving Magnus a detailed look. He had Sanguinius' eyes, the Second's hair, Dorn's determined gaze, Horus' charismatic air, and the indomitable presence of Manus. But the similarities ended there. His armour was of unknown livery, serpentine writing that bore a similarity to Old Earth's Aramaic tongue las-etched onto the pauldrons and sections of the chestplate. A black scorpion covered his right shoulder while a white scorpion covered the left.

Who was this? He was not one of Magnus' brothers, not exactly, yet there was a familiarity, a kinship, if not by creation than at least by concept. Magnus stared at this primarch, thoughts and words passing to him. It seeped through, almost unwittingly, most of it meaningless without context. Battle of the Ring, Shaaa Hydrades, Sunstone King, the First Ember, but one phrase above all stood out, repeated over and over again: the Antarus Apostasy. Antarus? Could that be him, could this primarch blessed by the Ruinous Powers be the Antarus in which a galactic civil war was being waged in his name, his forces arrayed against the Emperor in pursuit of the Throne? It seemed so.

Magnus' interest piqued more, but at that moment the primarch, Antarus, looked past the hololith of Terra and stared into Magnus' eye unblinkingly. That Lord of Scorpions spoke in a gravely tone that had voiced orders in a thousand campaigns, eyes staring at him that had done much and seen even more.

"I see you," he rumbled, baritone voice supplemented by the disturbed forces that hovered jealously over Antarus. The mirror began to shake.

Magnus withdrew his soul-essence, severing whatever tangible connection there had been and continued onwards, the shaking ceasing as he moved away. What were those? Magnus thought. It was a deviation, far different than the others. The threads that connected the universes were far more reaching than he realised. What wonders and horrors could be out there, what knowledge? What possibilities?

The Sorcerer-King reached the end of the hallway, opening the corroded doors with a thought, and strode into a chamber covered in runes and wards, attempting to hide the Staff's power from those who sought it. It took years of searching, of pacts made and deals kept, but Magnus had finally found it. He walked to the Staff slowly, its power field akin to a liquid he must wade through. His sons situated the thralls about the chamber in pre-planned patterns.

As Magnus reached the pedestal the Staff had been placed, he pulsed an order and the nine Sorcerers killed their thralls, using their powers to rip heads from frail shoulders with but a thought. The sound of tearing flesh was followed by blood squirting into the air, arcing over some Sorcerers and covering others as it fell to pool on the ground. As the lives of eighty-one thralls ended, Magnus' clawed hand grasped the Staff, the ward of containment broken fully, and he felt its power flowing through him. Futures and potential paths flashed through his mind, events that were to come and others that would never materialise.

At the Staff's head was the Tome of Destiny. Only Kairos could read it without issue as the Tome was notoriously uncooperative with all but its maker. Two pages were open before him. One was a page of truth riddled with lies and the other lies riddled with truth. He read both, eye scanning and searching for the validity in their warp-written words, seeking insight into the Great Mutator.

Finishing, he reached out his hand, opening a tear in reality to Tzeentch's Court, and out stepped Kairos Fateweaver. The Lord of Change had been unable to find the Staff, its location hidden from it, and eagerly reached for it. Magnus withdrew it several centimetres.

+The deal, Kairos. I've done my part, now yours.+

The Daemon Prince's beaked feathered face scowled but the daemon nodded reluctantly. It leaned forward, whispering into Magnus' incorporeal ears, telling him one truth and one lie about his future. None but the primarch and Tzeentch's Vizier knew what was said. The Staff exchanged hands. Magnus closed his eye as the daemon withdrew, the warp tear fading away as if never having existed. The Daemon Primarch stood still, processing what he had learned, contemplating the fate awaiting him.

Eventually he turned to his sons. +Time to go. There is a war to fight after all.+

It is unknown among the Thousand Sons what information was exchanged between the Crimson King and the Fateweaver after the primarch returned the Staff and its Tome to it, but it is known that Magnus departed the ziggurat to confront his two brothers. Magnus was a Daemon Primarch, the Chosen of Tzeentch, and the undisputed master of sorcery amongst his brotherhood, but he faced two Loyalist Primarchs, one who had always despised him and the other who once counted him amongst his few friends but now both desired his death.

And though he perished that day, Magnus was a prince of the warp, a Daemon Primarch who could never truly die, not even by a blow delivered by the Wolf King. Both Loyalist Primarchs suffered grievous injuries, Russ forced into a healing coma for months, but they prevailed nonetheless. Magnus, disappointed that neither Loyal Primarch had been killed, was nonetheless pleased by what he had acquired. Despite the Cyclops seeing Aginthon VII as a victory, the Thousand Sons did not. Nearly the entirety of the rebuilt Spireguard regiments had been slaughtered to a man; the Legion fleet thoroughly mauled, limping back to Sortiarius; and three hundred of the Rubricae were destroyed, though all but sixty had their souls recovered and returned to their original war-plate. More devastating than all that, however, was the loss of sixteen Space Marine Sorcerers, irreplaceable and nearly unmatched in psychic prowess. As a result the Fifteenth Legion would never again gather in such numbers, preferring small bands of a half-dozen Sorcerers or smaller with few warbands exceeding a hundred Rubricae.

It took centuries for Magnus to return to Sortiarius from the Court of Change but return he did. From atop his Tower of the Cyclops, Magnus sees and knows much of what happens in the Great Eye and the galaxy at large. Through his baleful eye, he peers into the hearts and minds of millions, planting the seeds of betrayal, ensuring that hundreds of rebellions erupt across the Imperium. It is believed by the Grey Knights that the Year of Tears came about due to Magnus' insidious influence. The Year of Tears was a massive rebellion that consisted of over two hundred worlds across three Segmentums. It would take the actions of several Sector Battlefleets, sixteen Space Marine Chapters and an estimated one hundred and ten million Guardsmen to put down these rebellions. This massive deployment and the bloody year of war that followed inadvertently weakened several sectors in Segmentum Pacificus. These underdefended systems were overrun by the destructive Ork Waaagh! of Snarog Ironbreak mere months later. What followed took several years and millions of lives before the greenskins were routed and subsequently exterminated. It is unknown if the Year of Tears and the Snarog's Waaagh! were both orchestrated by the Sorcerer-King, or if only one was and the other nothing more than happenstance.

The Traitor Primarch is believed to have manipulated events that led to the Battle of Midgardia in the home system of the detested Space Wolves. While several Thousand Son warbands were present at the battle, it was a loose alliance of traitors from multiple Legions and Chapters, whose loyalty was to one of the Great Four or to Undivided as a whole, yet it isn't doubted that the Exalted Sorcerer Madox was overall commander of the Chaos forces. The Space Wolves were able to fight off the assault though at great cost, Great Wolf Logan Grimnar having perished, Magnus was reportedly not displeased, merely saying to the Rehati that, 'The die has been cast, let us see where it falls.'

Magnus has occasionally ventured into the Imperium over the past ten thousand years, typically to recover lost artefacts of various import, or to initiate events that led to catastrophic chain reactions. The Fifteenth Primarch rarely fights alongside or leads his sons, preferring to despatch them to carry out tasks he deems too menial for the Chosen of Tzeentch. This has caused many to grow distrustful and despise their primogenitor, especially after the losses suffered at Aginthon VII. Some, such as Iskandar Khayon, the Eye of Sakaeron, have severed all bonds of loyalty to their gene-sire, giving their allegiances elsewhere. But a vast majority, despite the hate they feel for their primarch, would nonetheless rally to their Crimson King if he only so called.

And as the millennium comes to a close and the galaxy burns with never-ending war, many wonder, either in hope or fear, what the Red Cyclops of Sortiarius will do when the End Times arrive for they will soon be upon us.

---

Organisation-

The Fifteenth Legion's original structure harkened to the Officio Militaris' Terran Pattern layout which it would field until its primogenitor's discovery. The Legion grew steadily in its early years, its corps of psykers one of the largest in the nascent Legions, and soon enough the XV brought in many worlds into compliance, securing crucial victories in the Crusade's opening campaigns.

Yet once the tragedy of the flesh-change began, the Legion quickly dwindled in size, some of its brotherhood dying, a majority being placed into stasis. By the time Magnus assumed command of his sons, they numbered only a thousand able-bodied legionnaires. To honour their persistent resilience, the primarch named the XV the Thousand Sons.

The Crimson King enacted sweeping changes to the XV, moving away from the Chapters, battalions and platoons of other Legions, and implementing the Fellowships, ten in all. Each Fellowship would, in time, field at least a thousand legionnaires each and for a time this was maintained. Following the Kamenka Troika Campaign in which the Tenth Fellowship was nearly wiped out in its entirety, the number of Fellowships was permanently reduced to nine. Separate from the Fellowships were the three Red Orders, these sects centred on military matters rather than psychic. These were the Order of Ruin, the Order of the Jackal, and the Order of Blindness, each specialised to further the Thousand Sons goals on and off the battlefield.

The Cult Arcana were introduced, five unique Cults centred around specific psychic disciplines, with their members spread throughout the Fellowships to allow each Fellowship to have the foresight of the Corvidae, the insight of the Athanaean, the unrivalled biomancy of the Pavoni, the destructive power of the Pyrae, and the protectiveness of the Raptora. Each Cult was led by a Magister Templi, who oversaw the Cult's training and teachings. The Magister Templi were integral to the advisory body known as the Rehati, an inner council formed of the Legion's officers and powerful psykers. The Rehati's membership fluctuated endlessly, with Astartes rising in ascendance and falling from grace on a regular basis. The Cults, through their Magister Templis, vied for the primarch's favour incessantly, something Magnus encouraged as the Sorcerer-King saw the competition as beneficial to the Legion's refinement of skills and acquisition of knowledge.

Following the Great Heresy and the Rubric its Chief Librarian had cast, the Fifteenth Legion fractured into a multitude of warbands. In spite of this division, the XV can be united briefly under the command of its gene-sire, though since Aginthon VII this has been done rarely and never in as great of numbers as Magnus' first foray into the Imperium as a Lord of Tzeentch.

Warbands typically field a handful of Sorcerers, occasionally led by an Exalted Sorcerer. Underneath these sentient legionnaires are their Rubricae brothers who are commanded by the Sorcerers. The Rubric Marines act as bodyguards and the first line of defence, and whenever a Sorcerer takes to the field of battle, the Rubricae guard him without concern for their own well-being.

---

Combat Doctrine-

The Thousand Sons have long been a Legion that centred its combat doctrine around that of psykers and their esoteric abilities. Though a large segment of the XV was psychically-attuned, a majority were non-psykers, standard battle-brothers that carried bolter and blade to war over staffs and psychic hoods, yet they acted more as a support unit for the powerful Librarians who could change the tide of battle with but a thought.

The Thousand Sons maintained a fragile balance between aetheric and traditional warfare throughout the Great Crusade, but after the Burning killed so many of the Legion's battle-brothers, the Librarians gained even more prominence as they became the linchpin of the Thousand Sons military operations.

Ahriman's Rubric only exasperated this, as the non-psykers of the Legion became soulless husks of dust and ceramite. The past ten thousand years have seen the Legion prefer small skirmishes, duplicity and subtlety, hit-and-run tactics when need be in the never ending search for artefacts and scraps of information deemed worthwhile, but employment of dangerous warp powers on a vast scale is not unheard of, as entire worlds have been swallowed whole with warp-fire by powerful Exalted Sorcerers of the Thousand Sons. This makes them a fearsome opponent to the Imperium as a Rubric Marine requires no sustenance, no rest, is incredibly resilient to damage, and has zero concern whether it lives or dies. These legionnaires are more akin to Iron Hand battle-automata than Space Marines, yet it is their very nature that makes them so formidable a foe to so many.

A Rubric Marine can, in most instances, be brought back if 'killed' on the field of battle, as long as their power armour is recovered. The shattered husk of a soul can return, retrieved by ritual and sacrifice from the Great Ocean, and re-integrate itself back into its prison, repairing any damage wrought to it and ready to follow whichever Sorcerer links to it first. Whenever a Sorcerer is killed in battle, the link to its Rubricae is severed. Bereft of commands, the Rubric Marines will remain motionless until another Thousand Son Sorcerer can cast its control web upon them. The sole well-recorded instance of this occurred on the world of Dal'nhyar during M34 in which a Thousand Son Sorcerer was killed and the three Rubric Marines that accompanied it stilled as if frozen, remaining in place akin to statues. The Ordo Malleus was despatched to investigate. After ensuring no local witnesses remained to relay the event, the Ordo transported the Rubricae to Titan for study, under guard day-and-night by a demi-squad of Grey Knights for an estimated four thousand years for study and observation before their destruction was ordered by the High Lords.

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Recruitment-

After the Legion's revival by Magnus' hands, the XV recruited exclusively from Prospero. Due to its relatively small population when compared to Necromunda or Terra, this prevented any sort of rapid growth or substantial expansion of the Thousand Sons, yet Magnus remained insistent that only Prospero could provide the warrior-scholars needed to ensure Mankind's Golden Age.

Following banishment to the Eye of Terror in the Heresy's aftermath and the Rubric's unforeseen consequences, the Thousand Sons have found it a momentous struggle to replenish its numbers in any consistent way. Though millions of psykers are brought to or journey to the Planet of the Sorcerers every year, only a handful are selected to Aspirants for the Legion. And Magnus' gene-seed has proven difficult to procure as the primarch is oft away in the deep warp prosecuting the Great Game in Tzeentch's name. Few genetic samples can be extracted from Magnus, and much of what is suffers from various mutations and ever-shifting genetic instability. Only a handful of gene-seed is deemed stable enough for implantation. And it is here where the Rubric takes another toll upon the sons of Magnus for only the strongest, both in will and psyker ability, can withstand the agony as their body is changed far more than that seen by Imperial Space Marines, their soul tested by the machinations of the Great Mutator. If for any reason the Aspirant fails any of the tests Tzeentch lays against him, his soul is consumed and becomes one of the Rubricae. Those few, for only one in nine survive implantation, become Sorcerers of the Legion.

The exact size of the Thousand Sons is unknown. Some Inquisitors believe there are only mere dozens, others hundreds or a thousand, but a very studious few predict that the Fifteenth Legion numbers in the thousands, though admittedly only a few hundred are Sorcerers and amongst them only a few score are Exalted Sorcerers. If the Thousand Sons were ever to reunite under single leadership, the galaxy would be immersed in warp-fire and oceans would turn red with the blood of the dead.

---

Homeworld-

Prospero was a world of vast deserts, breath-taking oceans, and several wide rivers that acted as the Prosperine people's lifeblood. Around these rivers developed arable land on the fertile soil, giving birth to Prospero's early civilisations by its earlies human settlers. While wars were fought, empire rose and fell, the inhabitants of Prospero nevertheless endured onwards, its enclave-cities becoming beacons of progress and learning centres.

All that changed following the psychneuein's arrival during the Age of Strife. Most of the cenclave-cities fell, never to be recovered until Magnus' campaign of reclamation, and three-quarters of the population died before Prosperine scholars and psykers erected effective kine-shields around the last few dozen cities and prevented Prospero's destruction at the hand of the warp-xenos.

After the Crimson King united his people and returned humanity as Prospero's undisputed masters, the planet entered a golden age. It would be solidified and made more glorious upon integration into the Imperium years later. For close to two hundred years the Thousand Sons homeworld was a safe haven for the unknown, the banished, the arcane, the misunderstood, those wishing to expand the human mind and pave the way to a future of unbound potential.

That potential would be forever barred once the traitors' manipulated the astropathic message to Leman Russ, editing its content from capturing Magnus to executing him due to his psychic assault on Terra. Prospero's fate was sealed as the Sixth Legion arrived in-system, no matter the courage and tenacity of its defenders. The Burning of Prospero was short, deadly, and saw an entire people nearly wiped out. The Thousand Sons, now branded as traitors, reluctantly joined Fulgrim's rebellion, helping pave the War Commander's path to Terra. For seven years the only homeworld of the XV was their battle-scarred warships, carrying those few mortals and legionnaires that escaped extermination at the Wolf King's hands.

Testimonies from captured Thousand Sons during the Heresy and afterwards revealed after much… persuasion at the hands of the Inquisition that Magnus had intended to return to Prospero after the war's conclusion when the Arch-Traitor became the Second Emperor. The Red Cyclops intended to rebuild what had been destroyed and reacquire what had been lost, further supplemented by the powers and knowledge bestowed upon him by Chaos.

Yet this was not to be so. Fulgrim's death by the Emperor's hand drove the rebellion into defeat. Now bereft of leadership, the Traitor Legions fractured, and the Thousand Sons fled real-space, knowing their destiny lay not in the Materium but in the Great Eye. There the Legion discovered Sortiarius, the Planet of Sorcerers, crafted by Tzeentch's will and gifted to the Fifteenth Primarch.

It is a rocky world, violently volcanic with ever shifting continents. The air is awash with warp energy, the planet a locus point of vast amount of Empyrean power flowing through it, allowing the Thousand Sons to carry out diabolical world-shattering rituals. It is a world where lightning storms are the norm, the sky dark with restless dead, and the oceans, in cruel parody of Prospero's beauty, are liquefied warp-matter, giving birth to horrendous creatures that wander the planet alongside billions of mutants, thrall wizards, serfs, warp-predators, Tzaangors, and Chaos Spawn that call that hell-touched world home.

Encircling Sortiarius is a spectral white ring of tormented souls murdered by deceit, a stark contrast against the red and violet of Eyespace. Nine suns give the planet its unnatural light, and the surface is covered in villages and cities that come and go, some lasting millennia, others minutes, appearing and vanishing on the God of Lies' whim or the experimentation of the Daemon Primarch. While Sortiarius is ever changing, as befitting the homeworld of Tzeentch's Chosen, the sole area that features any true permanency is Tizca. The City of Light was pulled from Prospero after the Wolves departed in the Hunt for Magnus, its ruins imbued with death, despair, and broken souls. When the Thousand Sons arrived to the Planet of the Sorcerers, pulled to it by Tzeentch's siren call, Magnus landed in the city he had been raised in and there amongst his greatest failure he reached apotheosis, ascending to daemonhood. From his cataclysmic rebirth, the world shaking in anticipated agony and insight, rose the Tower of the Cyclops from where Magnus would rule from for over ten thousand years, watching, waiting, readying for the time to return once more to the Imperium.

While the primarch resided in his Tower more oft than not, so too did his sons who found themselves on Sortiarius. The Silver Towers of Tzeentch float across Prospero, a majority ruled by a Thousand Son whilst others were ruled by favoured mortal thrall-wizards. These Astartes-ruled Towers are the private sanctums of the Sorcerers, typically only staffed by Rubricae and mortal serfs whose ancestors had served the Chaos Lord for centuries to millennia. It is here they conduct their experiments, plan their power plays, and organise raids into the Imperium. It is not fully understood how the Towers work, but only that dangerously powerful daemons of Tzeentch powers them. It is rare for a Silver Tower to leave Sortiarius, much less the Eye, but on the occasion one is spotted in real-space the High Lords despatch a strike force of Inquisitors and several Grey Knight squads to eliminate the threat before it can fulfil its nefarious mission, whatever that may be.

---

Beliefs-

Once considered among the most loyal to the Emperor, the Thousand Sons have fallen far from grace. Their belief that knowledge, no matter its contents or the dangers it must pose, should never be censored or prohibited from being researched. The Emperor's Edict at Nikaea saw to the Imperium officially accepting the use of psykers in its myriad forms, from astropath to Space Marine Librarian, yet it also brought the XV to censure, chastising them for what others saw as reckless abandon in delving into forbidden studies and digging up things better left forgotten. Since their fall to Chaos, the Cyclops' sons remained unchanged in their pursuit of knowledge whether it be for the betterment of the Legion, of Mankind, or their own fortune.

Magnus, once beloved by his Legion entire, is now reviled and revered in equal measure. A Daemon Primarch, a Prince of the Immaterium, and the Chosen of Tzeentch are just a few of the Crimson King's titles. Some of his sons have followed their father in the worship of the Changing God, believing the Architect of Fate to be the beginning and the end. Many more mirror Ahriman the Exile's views of acknowledging the existence and power of Tzeentch yet refusing to debase themselves in worship to what they believe to be a false god, and yet still respect or at least grudgingly follow their primarch. A handful, like Iskandar Khayon, detest Magnus for what he has done and what he has become, believing him to be the source of all the misery and misfortune that has befallen the Fifteenth Legion.

While opinion over Magnus is varied, the views the sons of the Cyclops hold for the Imperium are universal. They detest what the Imperium has become; that it has embraced religion and denigrated ideals the Imperium had been built on. They see it as a violation, a bastardisation of what had been nobly fought for and constructed millennia ago. Some Thousand Sons have fought more actively in the Long War than others, but all wish to see the Imperium torn down. The call-to-arms to join in on Sakaeron's invasions grows as the Eleventh Vengeance Crusade nears.

---

Gene-seed-

The XV never had the genetic stability of their fellow Legions such as the Dark Angels, Iron Warriors, Ultramarines or Luna Wolves. Even when Magnus suppressed the gene-seed, albeit temporarily, the rate of compatibility and implantation success rates were relatively low compared to most other bloodlines. Following the Heresy and the flesh-change's insidious return, few Aspirants survived and those that did quickly became heavily mutated and dangerous to their brethren. Many were killed by others in self-defence or interred in stasis to be used in cas Sortiarius was ever attacked, but a handful still wander the Planet of Sorcerers to this day. It was only after the harrowing Rubric that the Thousand Sons were once more able to recover, albeit with eight out of nine Aspirants becoming Rubric Marines with the sole survivor joining the ranks of the elite Sorcerers.

---

Battlecry- 'All is Dust' was once a common Thousand Son mantra on the cyclical nature of the universe, explaining that from where life arose whence it would always returns, and so the cycle has repeated throughout history. Since the Rubric, it has taken on a resigned bitterness by those few within the Legion that have retained their identity while so many of their brethren became Rubric Marines, hollow shells controlled by brothers who have lost hope of ever seeing their return.

Ten thousand years passed before he returned. The gate closed behind him, the silence within fading as the violent storm ahead of him raged on. Lightning struck the ground in intricate patterns, thunder rumbled as it answered prophecies whispered from bloody lips millennia before. Above circled several feather winged creatures, screeching hoarsely at his arrival.

Though his helm was melded with his skin and filtered out much, he could swear he tasted intrigue, ambition, anger, and perhaps even a little surprise upon the wind of wailing souls from those that detected his arrival. In the distance lay the destroyed City of Light, never rebuilt but always kept around as a painful reminder. In its centre where once the Pyramid of Photep resided was now an unblemished silver tower that rose high into the air. Atop of it glowed a single baleful eye. The Eye of Magnus immediately focused on Sortiarius' new arrival.

+Father, I have returned.+

+So you have,+ came the unrestrained force of the Sorcerer-King which caused the legionnaire to wince, blood trickling down his nose. +Attend me, Ahzek. We have much to discuss before the Final Crusade begins.+

+By your will, sire,+ Ahzek Ahriman responded, beginning the journey to the Tower of the Cyclops that could take hours or weeks, depending on his primarch's desires. Endless searching had turned up little and less over the centuries, but just enough information had been gleamed and artefacts secured that Ahriman was certain he could correct the Rubric. The Thousand Sons would be saved and woe betide the Imperium who had cast them out, for the Emperor's fallen Angels of Death were soon to return home under a single banner and thus usher in a new glorious era.

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Author's Note:

At long last, here they are: the sons of Magnus the Red, Sorcerer Lords of Chaos!

Hope you enjoy! If you do, please like and comment, let me know what you think of the story as a whole or the Index itself. Thank you for the amazing patience and support from you all. Y'all are great!

Next up will be the Sons of Horus Index, but that will be after I do several other projects that I should have gotten to long ago. Namely:

-Editing the Sanguinary Heresy Imperial Fists Index for SirDrakos, his story is on this website.

-The second arc of From the Ashes Reborn - A Dornian Heresy Continuation Story.

-The War of the False Primarch set in the Fulgrimian Heresy universe. It'll be similar to the Badab War chapter in structure.

-A collaboration/crossover piece written for the Legions Reborn project, involving a Thousand Son Sorcerer mentioned in this chapter venturing into an Alternate Universe, one in which there are 18 different Legions and a much different war known as the Antarus Apostasy. At the very least, check out some of their art over on Facebook dot com created by Slaine69 over on DeviantArt. They're glorious. So there'll be a FH-verse OC being sent into another AU where things are similar yet entirely different.

I understand that the FH Thousand Sons are similar to canon. I kind of put myself in a corner making Magnus go Traitor and become sworn to Tzeentch as per canon. That's an unfortunate side effect of having some Legions have the same allegiance as what we see in canon W40k.

I did try to alleviate this by adding new stuff, such as a slightly more effective Rubric, the Aginthon VII battle, the Year of Tears, blanketing Sol with a veil to prevent astropathic communication during the Siege is a main reason why the Ultramarines and Thousand Sons Indexes took so long. They are Legions whose allegiance and fate is largely the same as canon which then is difficult to write as I was a little creatively constrained.

It is unfortunate, but a main selling point of this Alt-Heresy is the mixed loyalties (Sons of Horus and Imperial Fists being loyal/ Word Bearers and Iron Hands being Traitor etc.)

The Sons of Horus Index should be quicker to write and be very interesting, that is when I start it after completing previously mentioned other projects.

The Word Bearers, Salamanders, Raven Guard and Alpha Legion all have the same allegiance as canon but I believe I've changed just enough to make them interesting and different enough.

The Word Bearers having to choose Fulgrim as Arch-Traitor, being part of the Syndicate Chaotica, and several other things that I won't reveal just yet due to spoilers. The Salamanders being the Regents of Mars and fighting off the Night Lords during the Heresy. The Raven Guard having a close relationship with the World Eaters who are close to the Astartes that will become the Chainsworn, plus Corax dying during the Scouring. The Alpha Legion with Omegon being a Loyalist and becoming Janus.

I hope you are as excited as I am for the future of this story. Only 5 Legion Indexes to go. I am unsure if I will continue into the End Times, as I will certainly take a break from the FH-verse after the Alpha Legion Index, but I am laying the groundwork in case I do decide to proceed with the End Times.

Again thank you all for the support, reviews and PMs! Very happy that so many enjoy it. See you next time.