Rivalonian heresy

by Jewsheisty

This is an alternate horus heresy fanfiction where the legions with the most bitter rivalries will instead have the closest ties of brotherhood. The first chapter will be an overview of the heresy, containing not too much detail, within the Index astartes chapters I will include details and fan favorite characters a lot more. heavily inspired by The Roboutian Heresy by Zahariel

Rivalonian Heresy

This is an alternate horus heresy fanfiction where the legions with the most bitter rivalries will instead have the closest ties of brotherhood, in the heresy of Warhammer 40k canon there are six main rivalries, these being the Emperor's Children and Iron Hands, the Iron Warriors and Imperial Fists, the Word Bearers and the Ultramarines, the Space Wolves and Thousand Sons, the Death Guard and White Scars, and lastly the Dark Angels and Night lords. I will only be using four of these rivalries with 2 being unused. The first chapter will be an overview of the heresy, containing not too much detail, within the Index astartes chapters I will include details and fan favorite characters a lot more. This is heavily inspired by The Roboutian Heresy by Zahariel

Pre Heresy

Ullanor

The lines of heresy were truly drawn at Ullanor when the future arch traitor Horus Luprecal of the Luna Wolves was raised above his brothers to Warmaster of the Imperium. Furthermore Magnus the Red and nearly his entire legion were to be taken to Terra to help the Emperor of Mankind with a secret project, igniting the jealousy of many, even Horus, for despite his new position as Warmaster the Emperor still felt that he wasn't worthy of knowing his plans. The decision of Magnus being brought back to Terra also ignited the suspicion of both Mortarion and Covus Corax who both despised psykers, it was the suspicion of these 2 primarchs that began the Nikea movement.

Nikea

With psykers being under heavy scrutiny after many warp tainted planets were discovered the Emperor felt the need to call the council of Nikea where the fate of psychic powers would be decided, Mortarion and Corax would argue vehemently against psykers with him claiming them to be a threat to the entire imperium, while Perturabo argued that psykers were a weapon like any other and to not use them would be needlessly costing the lives of many, Russ who nearly all thought would argue against psykers instead argued for them on account of his recently made friendship with Magnus.

The Crimson King himself stayed out of the debate stating that he had too much of a personal stake in the matter to be trusted with arguing for or against it, leading many to respect him for his restraint. In the end, the Emperor, hoping to appease both sides, decided on the librarian compromise that would see the use of psychic powers restricted and monitored, however Corvus and Mortarion both left the meeting with anger in their hearts. Shortly after the Edict of Nikea was decided the emperor announced that he would name his Praetorian, a title all suspected to go to one of the siege masters, Dorn or Perturabo, who despite them both being siege masters viewed the other with contempt, the Emperor however showed his pragmatism and wisdom instead announcing both primarchs would build and fortify the imperial palace, something that us in the Imperium today are eternally grateful for.

Monarchia

A few months after Nikea the Emperor took the Ultramarines to the world of Khur where the Word Bearers had converted the planet to the Lectitio Divinitatus and worship of the Emperor. Monarchia, its capital, was dubbed by Lorgar to be the perfect city. The Emperor who was disapproving of himself being worshiped would order the Ultramarines to raze the city from orbit while the Emperor chastised Lorgar and the XVII legion. Guilliman, Primarch of the Ultramarines, would feel extremely guilty for this act and would apologize to Lorgar profusely, vowing never to betray the Aurelian again. His faith in the Imperium and his father was also shaken to its core by this event and he would experience his first feelings of treachery. It was this vow that would push Lorgar to reach out to the Ultramarines and their primarch after his pilgrimage and pull them into heresy.

'Call on me in any endeavor, brother, and I swear that me and my sons will answer with all haste and strength'

Robute Guilliman to his brother Lorgar shortly after the razing of Monarchia

The Heresy

Just as the Imperium seemed to be the dominant force in the galaxy, treachery struck as five legions declared themselves traitors to the throne, The Sons of Horus, World eaters, Blood Angels, Death Guard and Salamanders attempted to purge their loyalists in the Istvaan III atrocity.

'We are betrayed'

Unknown loyalist astartes on Istvaan III typically attributed to Garviel Loken captain of the Sons of Horus 10th company

'We have been betrayed by those we once looked up to, by those we once aspired to be, now we will show them a savagery long suppressed by the supposed Angel, we will tear them limb from limb like the IX of old!'

Nassir Amit, The Flesh Tearer, Loyalist Captain of the Blood angels 5th company rallying his loyalist brothers upon discovering the betrayal of Sanguinius

The Eisenstien, a death guard frigate and battle captain Nathaneil Garro of the 7th grand company of the Death guard had brought the news of the heresy to Terra, the Praetorians and the Emperor intent on striking down this madness. Just over three months after the original betrayal in the midst of assembling a armada to bring retribution to the traitors when a damaged Gloriana class battleship arrived at the edge of the Sol system, to the shock of all present the ship was full of the few surviving loyalists from the traitor legions, the very same that Garro had thought he abandoned at Istvaan. At the head of this vessel was a mysterious figure who requested an audience with the Emperor, a revelation occurred on that day that would send shockwaves throughout the imperium for ages. The leader of this ship now identified as the Beta was one of the twin primarchs of the Alpha legion, Omegon, he went on to explain that Alpharius, his twin, had betrayed the emperor, along with another nine legions adding five more onto the already dreadful tally of traitors, it was revealed that along with the initial five legions the White Scars, Raven Guard, Ultramarines, Word Bearers and Alpha legion had spit on their oaths to the Emperor and joined Horus. Omegon had already installed agents in nearly every traitor legion and had the few legionaries that were loyal to him on their way to warn the eight loyal legions.

'I shudder to think of what would have happened had Omegon not revealed the true scope of treachery to us'

From the writings of the Praetorian of Iron, Perturabo

The 4 primarchs on Terra planned to counter the traitors, they assembled what became known as the retribution armada, one third of the VII under Alexis Polux one one fourth of the IV under Barabas Dantioch and one tenth of the XV under Menes Kalliston were assembled. They departed with the intention of crippling the vast industrial power of Ultramar.

Battle of Nocturne

One of the first major actions of the Heresy was the battle of Nocturne, Konrad Curze and the majority of the VIII, warned by agents of Omegon, attempted to land an early and decisive blow against the traitors went to the Salamanders homeworld of Nocturne and for a week, laid waste to the system. In a rage the Salamanders returned with Vulkan at their head, an intense battle was waged with the Night lords retreating to the Thramas cluster after being bloodied by the Salamanders, here they would wage war against the Salamanders for the first year of the heresy. Many astartes died on both sides, but the stealth of the Night Lords was a decisive factor and saw the VIII legion lose much less than the traitors. Even with the Night Lords slowly winning it would have been a long conflict based on attrition. That was until the Dark Angels, returning from their pacification of the Kephet empire within the Ghoul Stars arrived to assist the Night Lords, the XVIII who had until now been confident in their chances of making the VIII obsolete in the heresy suffered a decisive blow as they were caught against the full strength of both the I and VIII legions, Vulkan and Conrad entered their first duel of the heresy.

Both brothers fought with utter hate for each other but eventually Vulkan retreated as nearly all of his Pyre guard died around him. With the defeat of the Black Dragon at the hands of the Night Haunter the Salamanders fled to the Thramas Cluster.

'Do not be dissuaded brother, the shadows will be your downfall! You will never escape them!'

Konrad Curze upon the retreat of Vulkan

Burning of Prospero

One of the other first actions of the heresy was the siege of Prospero. The Raven Guard and the White Scars emerged from the warp in the lightly defended prospero system, with Magnus and most of the legion on Terra the loyalists were disgustingly outnumbered, despite this the defenders were determined to make the traitors pay for every inch of ground, it was thought by the traitors that there was no significant loyalist presence close to prospero, this turned out to be a fatal mistake as Leman Russ and his Space Wolves emerged from the warp, responding to the distress call put out by the commander of the defense on prospero, Iskandar Khayon.

The Vlka Fenryka cut through the back of the traitor fleet and landed in the besieged city of Tizca, with the VI and XV fighting together they slowed the advance of the traitors to a crawl, despite the prowess of the defenders and the Wolf King himself, they were simply too outnumbered, with Russ being unable to lure either of his treacherous brothers into a duel.

Despite this the siege of Tizca crawled on into its fourth month. The traitors growing tired of the siege called upon reinforcements, the call was answered by none other than Angron who brought with him nearly is entire legion, with the arrival of the World Eaters legion the traitors steamrolled and overran nearly ever bastion until the defenders were corralled into the city center under the great pyramid, as the battle raged on inside the structure the Thousand Sons sorcerers prepared a spell at the same time the surviving void ships of both the Prosepero defense fleet and the VI legion fleet made a suicidal run at the planet bringing them just close enough to be within range of the Thousand Sons and rune priests warp fueled teleportation.

Once the loyalists were on board they fled the system being hounded by both the V and XII legions, while Corax and his forces began to channel the powers of the warp and prospero in order to ascend to daemonhood, becoming the first of his traitorous kin to do so. Ironically, despite Covus Corax being one of the most anti-psyker primarchs in the imperium, he along with his legion fell into the worship of Tzeentch, the most sorcerous of the Chaos Gods, what compelled him into falling so far from his original beliefs is unknown to us, but it has earned him the ire of Mortarion who views him as a weakling and coward.

With the ritual complete a massive amount of psychic energy was gathered allowing Corax and the Chaos Gods themselves to launch an attack on the Emperor's secret webway project forcing the Emperor to sit on the golden throne for the duration of the heresy, at the apex of the ritual prospero was destroyed and the XIX left to join the war in the Thramas cluster.

'The changer of ways shall guide us to the defeat of the false Emperor!'

Corvus Corax upon his ascent to daemonhood

Thramas Crusade

Horus recognized the threat that the I and VIII legions posed to his rebellion so he sent the XX, bringing them away from their push to Terra and Alpharius' obsessive search for his twin, and the XIX fresh from the burning of Prospero, to the Thramas cluster where the 2 loyal legions were planning their next move. What followed became known as the Thramas crusade, it was a game of cat and mouse between the four legions where void combat and boarding actions dominated more conventional war tactics. Not much is known to us of the thramas crusade however it is stated that the primarchs only met in open battle with each other once, this coincidently was near the end of the four year crusade, the battle resulted in the retreat of the traitors from the thramas sector, but they had set out what they wanted to do, and had prevented the 2 loyalist legions from reinforcing both Terra and the rest of the galaxy. With the I and VIII ships heavily damaged they weren't able to return to the heresy until it was at the close of its fifth year.

Battle of Phall

The retribution armada that was assembled in the sol system had been delayed by the warp storms that had sprung up across the galaxy in recent years and emerged from the warp haphazardly and damaged, the fleet was only kept together by the iron will of its three commanders Menes Kalliston, Alexis Polux and Barabas Dantioch. For weeks they waited in the Phall system, a backwater cluster of worlds out of the way of any real warp routes, or imperial military focused worlds.

This was until a massive armada emerged from the warp, the 2 largest legions the XIII and XVII had brought nearly their entire warfleets to the Phall system guided by their malignant allies in the warp and intent on crushing the retribution fleet, the loyalists however had been expecting this and had already devised a maximum efficiency defense plan with the sole objective of forcing the traitors to suffer. However even with the most optimistic estimates the forces of 2 traitor legions was impossible to fully counter with the forces under their command, for hours the 2 fleets battled with each other, some of the most skilled and talented void strategists would look back upon this battle and see that the commanding of the 2 fleets was a feat that today in the Imperium would be utterly impossible, hundreds of ships fought and maneuvered with perfect precision, intent on inflicting death upon the enemy.

Despite the valiant efforts of the loyalists, the traitor forces under the command of Guilliman, the most strategically talented of the primarchs, were too much, both sides knew that the second the loyalists attempted to escape it would be a slaughter, in response to this realization Menes Kalliston, one of the most powerful magisters of the XV sacrificed himself. Him and all but one of his most powerful librarians formed a massive psychic shield in the void before detonating their own ships warp reactors, the combination of the immense psychic energy and the volatile warp detonation caused a massive tear to open in space

The loyalist retribution armada was prepared for this hence had their gellar fields active, the closest traitor ships weren't as lucky and dozens of traitor vessels were sucked into the warp tear never to be heard of again, with the sacrifice of nearly all of the Thousand sons forces the remaining few fell under the command of Revuel Arvida, a skilled librarian of the Thousand Sons, and the marine that Kalliston had chosen to be his successor. The remaining forces of the retribution armada would be drawn to a small flare in the warp that allowed them to guide themselves through the warp in the absence of the astronomicon due to the ruin storm, when they emerged they found themselves in a place that none would have expected.

Path of fire

After the losses taken by the Salamanders in the battle of Nocturne and the Thramas cluster ambush, they would not wait to recoup their numbers like Curze and the Lion believed and instead would launch themselves on a campaign against the imperial worlds in coherence with the Warmasters own, this was a massive problem for the imperials as there was no legionary force that was able to respond to the threat of the Salamanders besides a handful of small company sized garrison forces from nearly every legion that began to coalesce into a fleet that was about 10-15 thousand marines strong, nothing compared to the entirety of the XVIII.

With the sons of Vulkan burning across the imperium the scattered loyalist marines and the hundreds of regiments of imperial army forces attempted to hold them back, despite their efforts slowing the campaign of the Path of Fire it was still conquering dozens of worlds.

Until the battle of Tallarn, Vulkan in order to better conquer the lightly defended worlds had split his fleet multiple times. However when he came upon the world of Tallarn he gathered his entire legion and made planetfall capturing and fortifying over a third of the world before stopping his advance mysteriously. Days after the Salamanders made planetfall millions of imperial army and mechanicum forces arrived not knowing why Tallarn was significant but knowing that they could deal a powerful blow to the traitors if they were to defeat the Black Dragon and his forces.

Thousands of tanks, hundreds of knights and dozens of titans made planetfall and began engaging the traitor forces, soon the auxiliary forces that had arrived alongside Vulkan were defeated and despite the XVIII primarch having tens of thousands of legionaries under his command he acknowledged that engaging titans and knights with astartes was foolish, hence he retreated from the planet and made way to his next target, Nostromo.

'The truth I have spent my life searching for is revealed to me. I do believe that it's time I crush my dear foolish brother'

Vulkan the Black Dragon after the Tallarn Campaign

Flight of the Wolf

For five entire years of the heresy a brutal battle was being fought in the far reaches of the imperium, ever since the culmination of the burning of prospero the World Eaters and White Scars had hounded the Space Wolves and Thousand Sons survivors. In Imperial records we don't know much about the time that was known to the VI and XV as the Flight Of The Wolf, however we have reclaimed some accounts of these days. Namely that the Wolves of Fenris and the Thousand Sons survivors fought a tactical retreat while the White Scars and World Eaters Chased after them with reckless abandon.

We know of at least 3 battles that took place during the Flight, the first battle of the Alaxxes Nebula, a massive void conflict between the two forces. The Battle of the Storm Wall, where the main World Eaters fleet ignored any tactical insight into the battle and charged the Space Wolves on the edge of the ruinstorm, severely bloodying both sides and the siege of Kreig, a key world which served as the sight of the ascendency of Angron to a daemon prince and the official end to the Flight.

The survivors from Prospero were able to deal significant damage to both traitor legions and Angron in his new state slaughtered both White Scars and Space Wolves indiscriminately. After this campaign the White Scars and their Khagan would despise the World Eaters, even now in the 42nd millennium the V and XII legions are rarely seen working together. With the White Scars having to recoup losses from both the loyalists and Angron, and the World Eaters moving off to please their new god with skulls and blood. The Space Wolves and Thousand Sons retreated to Fenris to recoup losses and repair their ships.

Siege of the Pharos

The retribution armada had traveled through the warp to the only thing that they could see at the time, a dim astronomicon like light that shone throughout the sea of souls. It was revealed to be the planet of Sotha to the shock of all within the retribution fleet it was in the realm of Ultramar meaning that their ships had passed through the ruinstorm without being irreversibly corrupted.

Upon entering the system they discovered thousands of men and astartes worth of disparate imperial forces all reeling from their own battles with traitor fleets, and attracted to the light in the warp in the absence of the astronomicon. The commanders of the retribution fleet descended upon Sotha and were granted audience with the current commanders of the world, Captain Adallus and the entire 119th company of Ultramarines along with Adenoid Theil and his 22nd company, as well as Xa'ven of the Salamanders "the Last Drake" and the majority of his 34th company.

Barabas Dantioch understood the working of the Pharos and after months of study was able to operate the beacon. Using it to assist loyalist fleets in their warp jumps, many loyalists would later recount their time in the warp when under the sway of the beacon as being calm and serene while it would also increase their speed by a huge margin. While the original plan was to use the Pharos to help warp jumps for loyalist fleets. Dantioch soon pointed the Pharos at Terra allowing any loyalist forces Blocked from the Astronomicon by the Ruinstorm to see Terra and travel towards it massively increasing the influx of both materials and soldiers to the Sol System.

The Pharos was starting to impact the traitors war effort and increase the loyalist morale and effectiveness. The Warmaster needed the beacon silenced and nearly took the XVI to crush the defenders on Sotha; however he was beaten to the punch by another. The original plan had been for the Word Bearers and Ultramarines to join the Push to Terra along with the Blood angels and Sons of Horus after the retribution fleet was dealt with. However, with rumors spreading that the remnants of the retribution fleet were the ones defending Sotha as well as the fact that Sotha was within the realm of Ultramar caused Gulliman to rage.

He along with half of his legion along with Lorgar and half of the XVII would crush the Loyalists in Ultramar. They left the other halves of their legions with the main traitor fleet under the command of Marius Gage and Kor Phaeron respectively.

Both the World and System of Sotha had been fortified to an extensive degree by the loyalists with Dantioch and Alexis combining their legions defense doctrines to create a near impenetrable fortress, combining this with Adallus's knowledge of the Ultramarines and Thiel's unconventional tactics, as well as Xa'ven's resilience and tenaciousness the system of Sotha was one of the greatest bastions of the loyalists aside from Terra, But they faced two primarchs and well over one hundred and fifty thousand traitor astartes, assisted by the daemonic. The outer reaches of the Sotha system housed a small belt of asteroids that saw the first void skirmishes between the 2 sides, with the loyalists using their knowledge of the system to out maneuver the traitor ships, however eventually the traitors were able to push past and destroy most of the fleet before landing in the orbital station of Sotha, defended by the 119th chapter of Ultramarines.

They would fight with all their martial fury and prowess, succeeding in holding the traitors for over 2 hours before Lorgar himself came forth with his Gal Vorbak and slaughtered the defenders of the station. Most of Sotha was uninhabited so the traitors focus was directed at the mountain and the fortified town around it, due to the lack of orbital defenses the warhost of the XIII and XVII landed without much trouble.

A battle was fought within the town that would last just over a week, where Imperial Army forces as well as a few squads of astartes held the traitors at bay. Even when the traitors had pushed out tha last vestiges of resistance the loyalists fought a guerilla campaign in the sewers of the town further delaying the traitor forces. After the city was taken Guilliman was faced with the more difficult challenge of ascending and entering the mountain. The defenders had fortified points along the slope and extracted a heavy toll from the Word Bearers and Ultramarines that ascended it recklessly. Despite the might of two primarchs the loyalists were still able to hold them for over a week and a half on the slopes of the hollow mountain.

Soon the traitors were faced with only two entry points and found that they couldn't easily break through either; Guilliman sent forth thousands of his sons but within the entryways to the mountain numbers counted for nought. For over three months this cycle would grind on with casualties mounting on both sides, the defenders however had already installed a fully functioning apothecarion within the mountain. Lorgar and Guilliman, growing tired of the slow progress, invoked a ritual that summoned a host of daemons within the Hollow Mountain pulling away many defenders from the front.

Lorgar and Guilliman along with their elite would assault and overwhelm one of the entrances and despite the maze-like structure of the mountain manage to push deep within it, guided by whispers that echoed from the sea of souls. Still, this process took time as dozens of fallback positions held the traitors at bay, for over a month the loyalists would hold their positions until their losses became too high. Soon the loyalist front was effectively cut in half with Alexis, Aenoid and Xa'ven cut off from Dantioch and Adallus. The loyalists would fight hard to defend the main Pharos chamber and relink but to no avail. Lorgar held the flank while Guilliman assaulted the main chamber, intent on slaughtering any Ultramarine loyalists. While he would succeed in killing Adallus the captain of the 119th, his true target, Aenoid Theil, would elude him. Dantioch seeing the chamber was lost, contacted the loyalist forces trying to relink telling them to evacuate the world, with heavy hearts the surviving loyalists bar the Warsmith and a few astartes teleported onto an Ultramarines cruiser in orbit commandeering it and escaping towards Terra.

In the Pharos chamber all but Dantioch had been killed, in an act of desperation the noble Warsmith threw himself into the core of the Xenos machine. Overloading it and killing many of the more tainted traitors, most however would survive, protected by the dark sorceries of their primarchs. Guilliman would be angered at the amount of damage done to his legion and curse the loyalists for not only causing him thousands casualties but also for destroying the objective and prize of the campaign. Nonetheless the siege of Sotha and subsequent destruction of the purifying Pharos beacon completed Ultramars descent into the madness and corruption of the ruinstorm.

'Let Ultramar be plunged into the realm of the Primordial Annihilator!'

Robute Guilliman upon the destruction of the Pharos device and the completion of the corruption of Ultramar

Wars of Ash and Gold

During the heresy the loyalists had devised a plan that would see nearly every traitor legion slowed by a loyalist one, there was quite a lot of success with most of the traitors being countered, however there was never a loyalist legion in position to counter the Death Guard.

Mortarion and his sons conquered and destroyed dozens of imperial worlds with barely any resistance. With the psychic attack on Terra Magnus couldn't take his legion to stop his treacherous brother as he and his legion were contained to the webway war. Due to the Thousand Sons presence in the webway and with both the IV and VII on Terra it was decided that a significant force of custodians would leave the Sol System and attempt to counter the Death Guard.

However even with the 5,000 custodians that Valdor planned to lead against Mortarion it was clear that it would not be enough to stop an entire legion. It was just a few days before the departure of the custodians that a sizable force of legion ships emerged near pluto. The ships were assigned to the XIX legion and were nearly fired upon, they would have been had it not been for Perturabo staying the hands of the loyalist defenders, he had recognized the signals of the ships and saw that they belonged to a force known as the Exiles. A group of Raven Guard that had been disgraced By Corvus simply because they were fighting as an attachment of the Luna Wolves and had methods he disliked. Arkhas Fal had chosen to not follow his gene-sire into betrayal, the reason for this in the 41st millennium has been lost however some inquisitors suspect it may have been nothing other than spite for Corvus and the rest of his legion.

Whatever his motives were it didn't matter at the time as Valdor quickly recruited the Exiles to assist him, there were just under forty thousand marines within the divergent fleet of Raven Guard. While the loyalists would still be outmatched the odds were somewhat evened now.

The first battle of the conflict that would come to be known as the Wars of Ash and Gold occurred on a world that had already been decimated by war. The Loyalists would ambush the Death Guard leading to a short void skirmish before the loyalists retreated into the Prospero system. After the loyalist fleet had retreated to the other side of Prospero and the loyal forces on the surface had reinforced the abandoned and partially destroyed defenses of Tizca.

The Death guard prepared to descend. Mortarion and his legion assaulted the defenders who had manned the already built defenses. For days the forces fought against each other in a war of attrition until the defenders allowed the death guard in, baiting them into a trap, Mortarion and his Deathshroud pushed into the great pyramid of Tizca, falling for the trap Fal and Valdor conceived. In front of Moratrion stood 20 Custodians and Arkhas Fal. 4 of the golden armored warriors approached Mortarion along with their Captain General. While the remaining 15 Custodians and Fal prepared to face down the 40 deathshroud and dozens of other legionaries that the Primarch of the XIV legion had brought with him.

Mortarion would face off against the custodes throughout the shattered form of the pyramid of Tizca sustaining many wounds due to the prowess of the Warriors of the ten thousand, eventually however he killed them all except for Valdor. Constantin's purpose had not been to kill Mortarion, as he knew it would take more Custodes and planning to bring down the fourteenth son of the Emperor; instead he had brought Mortarion up dozens of stories higher in the Great Pyramid. With the death of his 4th companion he used the bolter on his Guardian spear to break the window of the Pyramid and jumped out, sliding down the ruined structure until with a leap, he reached the ground, after this, he detonated explosives in the pyramid, severely interfering with the Death Lords ability to reach the ground. Regrouping with the other force of custodians he would discover only 7 custodes left, along with the Shade Lord, who to the surprise of Constantin had fought nearly as well as the custodians.

With that they recalled their forces, commanding them to perform a fighting retreat. With the death guard regrouping for another assault the Loyalists revealed their true purpose for selecting Prospero; they summoned the psychic predators of the planet to wreak havoc in the lines of the death guard. With the lack of Librarians and the ineffectiveness of Physical weapons the Death Guard evacuated from the world intent on exterminating it from orbit.

But they found that the Loyalists had also retreated, when Mortarion teleported back to his flagship he immediately ordered the exterminatus be canceled and prepare the fleet to pursue the Loyalists. What followed were years of war between the 2 factions. The war culminated in the battle of Catallus. Both void fleets engaged each other Mortarion fought Arkhas Fal and Constantin Valdor while the death guard siege master Kalgoro led an assault on the Shadowed Hand, the flagship of the Exiles. The Death Guard would assault the ship in dozens of areas forcing the Exiles to cede the ship to the traitor forces. Amidst the retreat Captain Balfur Ignus, second in command of the Exiles, would be killed by Kalgoro. Fal and Constantin would manage to fight back Mortarion and retreat to Terra. This battle would be the last official action of the Exiles with them renamed the Ashen Talons.

"We have done all we can against the XIV, now we return to the seat of power within the Imperium, together we will fight on the walls of the palace." - Constantin Valdor upon the completion of the Wars Of Ash And Gold

Battle of Nostramo

After the Tallarn campaign and the subsequent ending of the Path Of Fire. Vulkan gathered to him a great host of traitors, nearly every Salamander was present alongside a force sent from the Warmasters own legion, alongside the legionary contingent there were hundreds of thousands of cultists and traitor imperial army forces gathered. Vulkans objective was nothing short of the destruction of Nostramo and the VIII legion.

With his fleet assembled he made great haste for the homeworld of the Night Lords hoping to have already destroyed it by the time Konrad arrived. What The Black Dragon didn't account for however was the fact that Konrad had foreseen his brother's treacherous plans and had set up an ambush upon Nostramo. When the traitor fleet emerged from the warp they found that the night lords fleet had vanished, Vulkan was not cowed by this irregularity though believing the VIII legion fleet to be rushing to Nostramo through the impairing warp storms.

With brutal efficiency the Salamanders and supporting Sons of Horus descended on the planet initially facing small amounts of resistance but were soon met with ambushes caused by seemingly invisible foes, all throughout Nostramo Quintus squads of traitor astartes would go missing until after hours of the traitors wiping at shadows the night lords clashed against their forces in a lightning fast spearhead attack intent on the destruction the traitors and the death of Vulkan.

The Black Dragon's command base in the center of Nostramo Quintus was set on from all sides, hundreds of salamanders died in the confusion, however Vulkan soon got them under control, killing droves of VIII legion astartes with each swipe of his thunder hammer Dawnbringer with the traitors rallying around Vulkan they began to give just as good as they got and established a coherent defense.

Soon Konrad and his Altrementar came forth engaging with Vulkan and his Pyre Guard. After minutes of trading blows with neither primarchs drawing first blood Vulkan landed a titanic blow to the Nighthaunter's chest knocking him back through a wall and out of the city center. With the battle raging behind him, Vulkan pursued his brother. Konrad used the cityscape of Nostramo to ambush his brother, striking at him with a few blows before vanishing into the shadows when Vulkan attempted to counter him.

Eventually Vulkan found himself inside a large spire of the city, it was here that Konrad revealed his trap, knowing of the extreme resilience of Vulkan from their former duels, he had prepared a trap for the Black Dragon. As they fought Curze drew Vulkan further into the spire until he stood in a room full of unmarked canisters, with the press of a button Life Eater virus was vented onto Vulkan. Under normal circumstances he would have been protected by his armor but the lightning claws of Konrad had created slashes and rents in his Draken Scale armor.

The Life Eater virus poured into his armor burning and dissolving his body, even his perpetual status was not enough to protect him. It was then that Curze ignited the Life Eater virus with his master crafted bolt pistol, the Justicator. The black dragon was ignited in flames and he was being burned away.

In a shock he attempted to use the teleporter in his hammer to get back to his ship but Konrad seeing this charged the burning form of Vulkan and severed his arm, along with the hammer preventing his escape. He then point blank attached and detonated a melta charge to confirm the absolute death of Vulkan. With the loss of their primarch the traitor forces nearly broke, it was only the will of Ignatius Numeon that prevented the total breaking of the Salamanders and Sons of Horus forces.

The traitors managed to retreat to orbit while fighting off their pursuers but found their void fleet under attack from the Night Lords fleet that had appeared from the edge of the system the moment that the traitors made planetfall. Despite the horrendous losses suffered the traitors did manage to retreat and rejoin with the Warmaster in time for the Siege of Terra.

In the aftermath of the battle the VIII fleet had only a few warp capable ships, worse than this Konrad Curze had fallen in and out of a coma due to him taking brutal wounds from Vulkan and inhaling some of the virus when he used it on his wayward brother, he had time to order 2 of his captains, Krukesh the Pale and Gendor Skraivok the Painted Count, to venture to Terra with 7,000 night lords and Vulkans warhammer Dawnbringer as proof of their success. While Sevetar would take 90% of the remaining night lord fleet once it was repaired and wreak havoc on the worlds conquered by traitor forces. When Curze recovered he would take the remaining fleet and an elite contingent of night lords led by Talos Valcoran to assist in the throne world's defense.

The push to Terra

At the beginning of the Heresy, the Warmaster in cohesion with Guilliman created a plan that would see the traitors decimate the loyalists on every front. The Salamanders would cripple the Night Lords, and then embark on burning a path through loyalist worlds. Prospero would be destroyed while the World Eaters would engage the Space Wolves. The White Scars, after Prospero, would cut out vast swathes of the imperium in the name of the Warmaster. The Death Guard would be uncountered and destroy world after world. The Raven Guard, after Prospero, would venture to the Thramas sector and along with the Alpha legion, crush the I legion. Lorgar and Guilliman would destroy the retribution armada then regroup with the Sons of Horus and the Blood Angels to make the main push to terra.

However early in the war many of these plans were thrown to the side, the Night lords did heavy damage to the Salamanders, not the other way around. The White Scars were forced to join the sons of Angron due to dozens of thousands of XV legion astartes joining with the Space Wolves. The retribution armada retreated to Ultramar where there was an unknown loyalist rally point.

The Death Guard were countered and the Thramas crusade failed to eradicate the I or VIII legion. The Sons of Horus and Blood angels would be joined by roughly 40% of both the Ultramarines and Word Bearers legion however opposing the main push towards terra would be the forces of the Emperors Children and Iron Hands. They first clashed above the black sands of Istvaan V, where Horus had fortified ruins on the world in hopes of using the element of surprise as well as the not yet declared traitor forces to annihilate multiple loyalist legions. However, this was not to be due to the betrayal of Omegon.

Just as the Warmaster and Sanguinius prepared to leave the Istvaan system, the last of the traitors to do so as Horus wanted to ensure each of his brothers would follow his commands, a massive fleet dropped out of the warp.

Upon further investigation it was revealed to be the combined fleets of the III and X legions. Fulgrim was the first of the loyalists, besides Omegon, to learn of the treachery. Horus had taken a quarter of his traitor sons and attempted to sway Fulgrim to his side as the Phoenician was one of his closest brothers. Fulgrim was enraged that Horus would betray their father and fired on his fleet destroying over a dozen ships before the XVI were able to translate to the warp with the intention of rejoining their main fleet.

Realizing the Horus would have converted others to his cause Fulgrim called upon his closest brother Ferrus Manus, who had just finished a compliance in a sector only a few weeks travel away from the Emperor's Children. Upon his meeting with the Iron Hands he found an enraged Ferrus Manus, who had been informed of the treachery by an Alpha legionnaire giving the two primarchs the full scope of betrayal. Hours later another small Alpha legion ship exited the warp claiming to have been assigned to warn Fulgrim of the heresy, to the two primarchs the Alpha legion not only served as messengers but also as more marines to use against the traitors.

The fleet gathered nearly every asset the two legions had. It took time for this force to come together and it was assembled over a 2 and a half month-long period. Eventually they deemed their force was as much as it could be. They burned full speed towards the last known location of the traitor Warmaster, The Istvaan system. The two fleets would start their war at Istvaan and continue it across nearly the entire galaxy.

Champions would rise from both sides. To our knowledge the primarchs of the legions would meet in combat only once during this period. The battle of Molech would see the traitor primarchs descend onto the world to approach a warp portal.

The world was lightly defended and the Emperor's Children and Iron Hands were reported returning to Terra but as soon as the warp portal came into view there was a teleport flare revealing the Ferrus and Fulgrim along with their honor guards. The 4 primarchs battled with The Gorgon and Angel clashing in battle. The Warmaster and Phonecian also engaged in battle. At the climax of the battle Ferrus cast down Sanguinius with a mighty blow from Forgebreaker but was unable to finish him due to the amount of blood angels that fanatically threw themselves at the Gorgon.

Fulgrim, despite his righteous fury, didn't have the time or strength to kill the Warmaster. Instead he broke off from the Arch Traitors and killed over 50 of his elite sons before plunging himself into the chaos portal, along with an extremely powerful virus bomb intent on destroying the gateway from the inside. What happened within the portal we don't know however the Loyalists were teleported off Molech, Fulgrim included. Despite Fulgrims best efforts Horus and Sanguinnius both were able to enter the portal, both received a massive boost in power, with Sanguinius becoming the third of his brothers to ascend to Daemon princehood. The two loyalist fleets arrived at Terra with months to prepare for the siege.

Attempt on the Warmaster

With the Emperors Children and Iron Hands out of the way, and many of the other traitor forces defeating or pushing back their opposition the Warmaster desired a quick end to the war, hence he distributed his legions to capture the last few systems before mustering upon Ullanor.

Many of the traitor legion fleets would travel alone in this time however the Ultramarines and Sons of Horus traveled together. Due to the locations or insanity of the other primarchs the Lord of Ultramar and Arch Traitor planned the rest of the war as they went. Due to the unique vulnerability of the Warmaster, the enraged Leman Russ vowed to kill Horus before he set foot on Terra. He sent out an astropathic call to the Dark Angels and one of his closest brothers, the Lion, to join him in the attack. With the chances of reaching Terra in time for the siege slim at best, the Primarch of the 1st agreed.

As the two fleets joined both sent forces to Terra, 10,000 marines from each legion would venture to Terra, the Dark angels, under command of Lord Seneschal Corswain, while the Space wolves force was under the command of Wolf Lord Hvarl Red-Blade, captain of the 4th great company. Iskandar Khayon was also commanded by Russ to return to terra with his Thousand Sons, the XV legionaries would go but Khayon himself would remain stowed away on the Hrafnkel.

The battle of Trisolian Began with the 2 Loyal fleets emerging from a gravity well between the two stars of the system. The traitors only had a small amount of time to prepare. Horus easily predicted the goal of his two brothers and called on Guilliman to assemble an elite force and join him on the Vengeful Spirit. As the two fleets clashed over Trisolian V the Hrafnkel and Invincible Reason engaged the Vengeful Spirit and Macragge's Honor with the void shields of both ships being devastated, the XIII legion flagship was forced to disengage allowing boarding parties from both loyalist Glorianas to board the Vengeful Spirit.

Both Leman and the Lion landed in the hangar of the XVI flagship and, along with their elite, made quick work of the defenders. With the hanger secured they made a quick and deliberate assault towards the location they knew Horus would be, Luprecals Court.

One of the Deathwing squads carried breach charges, and blew open the sealed doors to the room, upon entering brutal fighting would break out between the elite of the four legions. Robute Guilliman strode towards Lion El Johnson while Leman Russ faced off against the Arch Traitor. Both duels were intense as the sons of the four primarchs clashed around the titanic duels taking place. It became apparent that, despite the recently awakened psychic strength that Guilliman wielded, the Lion was the greater duelist and he landed multiple blows on the Battle King of Macragge.

The battle between Russ and Horus was intense, both warriors struck at each other with speed and strength fueled by hate and resentment. Leman claimed the edge in speed and precision but Horus, as ever, commanded the advantage in sheer strength. Horus drew first blood, cutting across Leman's chest, not deep enough to kill or severely wound but it would be enough to slow the VI son of the Emperor down a bit. Three more deadly swings from Worldbreaker saw Russ put on the defensive, but in an instant he threw himself at the Warmaster, spear raised. The strike was perfect in execution.

The Emperor's spear pierced the Arch Traitors flank, stabbing deep into him. For an instant both Horus and Leman looked at each other hesitating as the clouds of Horus's corruption peeled back and he gained a moment of lucidity, but only a moment. With a mighty swing of Worldbreaker he sent Russ flying through the air and crashing against the obsidian black throne in the center of the Luprecals Court.

The Lion seeing this pushed Robute back and sliced deep across his chest, in a stunning show of prowess. He ran towards the form of Horus killing traitors as he went, when he was just a few steps away, theArch Traitor turned and swung world breaker in a wide arc, the Lion ducked under it and, using his speed, slammed his shoulder into Horus sending them both grappling, Russ, still reeling from the blow he took earlier, swung the Spear of the Emperor at the Arch Betrayer, cutting into his arm and allowing the Lion to plunge his blade into the wound created by Leman nearly killing the Warmaster there and then. But it was not to be, a portal opened up beneath the warmaster, teleporting him away from the two primarchs, as the ascended daemon forms of Corax and Sangunnius appeared on the bridge.

Both daemon primarchs had followed screams through the warp to arrive at this location. With the odds now drastically against them the Lion and the wounded Russ elected to retreat.

Despite the Attempt on the Warmaster failing and Horus surviving, the fleets of both the Sons of Horus and Ultramarines were vastly reduced and damaged, extending the amount of time Terra had to prepare as well as prolonging Solar War. Unfortunately due to the losses suffered by the I and VI legions they were forced to retreat and recoup the losses, making them unable to participate in the final battle for the throneworld.

The Solar War

The solar war was the longest campaign of the heresy, starting at the outset of the civil war and only ending when the Siege of Terra began. Within the sol system, there were officially three legions along with their primarchs however in reality the Thousand Sons had mostly been confined to a brutal and secretive battle in the Webway. This left the twin Praetorians Rogal Dorn and Perturabo to fortify the system, but more than that defend and purge it.

The Arch Traitor knew that the skills of both Dorn and Perturabo were legendary, hence he did everything in his power to prevent them from being able to cleanly prepare the Sol System. Horus, with the help of Corax and Alpharius initiated dozens of chaos cults that took the loyalists years to clear out, the traitors also sent flotillas across the warp to challenge Sols defenses.

Due to them having to travel huge distances through the warp without exit in order to reach Sol the traitor flotillas often emerged in disarray and confusion with dozens of ships lost to the tides of the empyrean, still it forced the Loyalists to be constantly on guard. As well as all of the subterfuge the traitors targeted Terra and the Sol System with, Mars and many of the titan legions had officially declared for Horus causing the need for thousands of loyalist astartes to be sent to the red planet.

However Horus underestimated the ruthless lengths that Dorn and Perturabo would go to in order to defend the cradle of mankind. The cults were wiped out completely within three and a half years. The two primarchs as well as their legions became extremely close over these years, with the VII and IV coming to respect each other immensely. Mars was taken in just over four years by the combined efforts of 1st Captain Sigismund, Captain Camba Diaz and Warsmith Barban Falk. While the war in the Webway continued Dorn and the Imperial Fists along with the IV legion and Perturabo, fortified the Imperial palace.

Perturabo had already created many void defenses for Sol to avoid marring the beauty of the cradle of mankind; he would continue in this task, creating hundreds of void stations and orbital arrays around the entirety of the Sol system, both Praetorians would also oversee the fortifications of the other planets within the Sol system, intent on making the traitors pay for each world with a mountain of corpses.

The legions on Terra spent the time bought for them by the other loyalists well, with Magnus and the Emperor banishing the daemon Drach'nyen and beginning to recreate the wards in the webway, instilling a wall within the webway preventing daemons and chaos from breaking through directly to the throneworld. The wall of psychic might managed to lessen the strain on the Emperor but still, the master of mankind was forced to remain on the golden throne to power and reinforce the wall. With the conclusion of the war in the webway the legions in Sol experienced a time of relative peace and with the arrival of the III and X legions their numbers were bolstered greatly.

In the time that became known as the Stall, all five legions recruited huge numbers from the populace of the Sol system, with many of these new recruits coming from the areas that the legions had recruited from at the outset of the crusade, eager to prove their regions were still worthy of the astartes legions. The Stall didn't last long however, and soon the armada of traitors had won the battle for Beta Garmon, the last gateway to Sol. The solar war would come to and end soon after. The traitors massed their fleets and pushed through the warp gates and mandeville points, intent on targeting Pluto first.

The numerous void stations of Perturabo would reap a deadly toll on the attackers, destroying hundreds of ships, but Lorgar and Guilliman would channel so much death and pain into the warp, that they were able to summon tides of daemons that appeared on the stations themselves. The mortal and transhuman crew remained firing for as long as possible, with some even being able to completely purge the daemons, but ultimately the stations that survived the assault of the neverborn would be forced to retreat or be destroyed by the armada of traitors. Each planet in the Sol system cost the traitors thousands. With the detonation of Pluto's moons being one of the most deadly operations the loyalists mounted.

Still despite the defenses, soon only Terra remained, as even Luna fell to the Lost and the Damned. The fleets of loyalists would retreat to the rings of Saturn where they would await the chance to assault the traitors yet again.

The Siege of Terra

With the conclusion of the Solar war the skies darkened over Terra as the armada of traitors massed above the throne world. The first landings of traitors would be decimated by the guns of the imperial palace. However not even the weapon systems of the Praetorians would be enough to prevent all the traitors from landing, the Iron warriors trenches would slow the traitors but through the weight of numbers alone the loyalists were pushed back to the walls, that was always expected however.

The traitors would force their way through the palace defenses at the cost of horrific casualties. Dozens of major actions would take place during the siege including the battle of the Lions Gate spaceport, the battle of the Mercury wall, the Battle of the Eternity wall port, The Saturnine Breach, The Sanctus Breach, and the most titanic of all, the Battle for the Eternity Gate. The traitors would throw themselves against the walls of the palace, creating gaps in the defenses; heroes rose and fell on the ground of Terra. The loyal legions spread themselves out amongst the defenses to delay the traitor astartes, as the siege ground on however Horus became more and more agitated with the slow progress and called upon his daemonic allies in the warp.

Corvus soon alerted the Warmaster that the Space Wolves, Dark Angels, and Night Lords were just weeks away from Terra. The Arch traitor knew that if the remaining loyalist legions arrived it would be the end of the heresy. Horus called upon his closest brother, Sanguinius, to assault the Eternity and end the siege. For this, the Fallen Angel gathered the entire might of the XI legion and marched against Ferrus Manus and the Iron Hands, who were holding the Eternity gate. Ferrus, intent on delivering a deathly blow to the traitors, counter charged the Blood Angels, engaging them on the ground outside the gate.

The battle was bloody on both sides, it wasn't long before the Angel and the Gorgon met in battle. The clash between them was titanic, while Ferrus held the strength advantage Sanguinnius was leagues faster, and with his ascension to daemonhood his prowess was only increased. They delivered blow after blow to each other as the Morlocks and Sanguinary Guard fought and died around them a Blast of energy from the Spear of Telesto sent Forgebreaker careening out of Ferrus' hands.

In response he used his necrodermis hands to grab the Spear of Telesto and throw it away from the angel. Sanguinius, hoping to end the duel, swung his Blade Encarmine towards the neck of the Gorgon, Ferrus however predicted the blow and caught Sanguinius's wrist in his hand, using the other to land blow after blow on the Daemon prince's unprotected face. Despite the countless blows rained upon him Sanguinius didn't relent, using both arms to inch the corrupted blade of his power sword closer to the neck of Ferrus Manus.

The Gorgon, seeing the infectivity of his blows, attempted to choke Sanguinius. With one Iron hand around the Daemon Prince's neck and the other holding back his sword. At the same time, Fulgrim and the majority of his Emperors Children were rushing towards the Eternity gate. Despite both primarchs being weakened by their brawl the Blade Encarmine and its corrupted energy field bit against the neck of Ferrus weakening his resistance, in an instant the Primarch of the Iron Hands was decapitated by Sanguinius.

Fulgrim and his reinforcements had arrived just in time to see Ferrus killed, in a rage the Phonecian drew Fireblade and took up Forgebreaker from where it was hit out of Ferrus's hands, charging towards Sanguinius who was still reeling from the damage done to him by the Gorgon. Fulgrim would land blow after blow on the primarch of the Blood Angels pushing him back. He would have struck him down had it not been for the timely arrival of Jahgatai Khan who was able to save the Angel.

Ferrus's body was stolen by the Blood Angels who dragged him away, much to the fury of the X and III legions. While the Iron Hands were nearly decimated, the reinforcements of the Emperors Children allowed the eternity gate to hold. Just hours after the death of Ferrus, Fulgrim would sally forth to assault Jahgatai Khan, the details of this duel are lost however we do know that they fought against each other with their godly blade skills and speed, however eventually Fulgrim was able to lay the Khagan low, when he returned to the walls his soldiers were perplexed to see him venturing back to the walls carrying the body of the Khan.

Days before the battle of the Eternity Gate , there was a breach created that threatened the sanctum imperialis, Angron himself led a massive host of traitor astartes in an effort to cut off the head of the imperial defenses. With Fulgrim repositioning and magnus tied up fighting the XIV and XIX Perturabo was the one that would be forced to confront his wayward brother, forming a force comprised of Imperial Fists and Iron Warriors he would devise a strategy to completely halt the momentum of Angrons assault. Perturabos forces would fight with shield and bolter, denying Angron and his warriors their desired melee combat, thousands of traitors were picked off by loyalist gunfire and some among the World Eaters would turn on their allies to sate the butcher's nails.

Angron despite being on the receiving end of thousands of bolter shells was still extremely powerful and fought a brutal duel with Perturabo, landing multiple blows on the praetorian that left rents in his armor and blood flowing down his body. However Perturabo utilizing the teleporter within Dawnbringer was able to get within Angron's guard and slam the hammer into his knee crippling him he raised it again making sure the power of the disruptor field was at full, slamming it down onto the head of the daemon prince and banishing his corporeal form back to the warp. Seeing the death of their primarch the World Eaters charged the gun lines of IV and VII legionaries even more fanatically, while most were cut down by bolter fire the ones that made it to the lines were able to wreak havoc among the loyalist astartes.

With the Sanctus Breach contained and the Khan's death stifling the constant assaults on the Eternity Gate, it seemed that a slight respite had come to the loyalists, their spirits were lifted when it was revealed that the rest of the loyal legions were just days from Terra. Fulgrim called for his brothers to meet within the Imperial Dungeons, there he revealed that before his death, Jahgatai Khan had told him of a plan devised by Horus and Alpharius to cripple the void shields of the Imperial palace and teleport directly into the throne room, while a diversionary attack was launched on the eternity gate.

While the primarchs would be in the Throne room awaiting the attack, Omegon went to the Aegis generator, hoping to stop the sabotage of his twin while the loyal Primarchs assembled their honor guard. Perturabo would sent the entirety of his trident to defend the eternity gate, Dorn would send captain Camba Diaz as well as Lord scheneshal Fafnir Rann, Magnus would have Phosis T'kar along with the majority of the XV legion defend the eternity gate, Fulgrim would send many of his lord commanders including Vespasian and 2nd and 3rd captains, Solomon Demeter and Marius Vairosean. The crippled Iron Hands would only be able to deploy a small amount of their legionaries to either engagement, but while the majority of the remaining Morlocks and Ferrum Court, the ruling council of the legion after Ferrus Manus's death, would assist in the throne room engagement, many legionaries would seek to defend the sacred ground where their primarchs fell, unwilling to see traitors seize the site of his death. It was on the 116th day of the siege that the void shields would fail, brought down by the sabotage of the XX primarch.

Omegon would arrive just in time to see his twin sabotage the void shield generators, The two primarchs would enter into a perilous duel, as Alpharius clashed his Pale Spear against the newly forged Lerna blade. The events of the duel between the two primarchs of the XX legion are lost to us as Omegon never spoke of what happened.

Back in the throne room, Horus made his move, ordering Guilliman and the near entirety of the traitor host to assault the Eternity Gate while simultaneously teleporting himself, Lorgar, Mortarion,Corvus, and Sanguinius along with their honor guards into the Throne Room.

Instantly the clash would be thunderous as the sound of bolterfire and clashing energy blades filled the Throne Room. Desiring to see an end to the battle and Heresy both sides fought with supreme fury and determination. The final battle of the Rivalonian Heresy would see nine of the emperor's sons do battle. The terminators and elite of the present legions tore at each other as dozens of duels erupted that, had they occurred on a lesser battlefield, would have demanded the attention of thousands, but every individual battle between astartes and custodians would take second place in comparison to the battles of the primarchs.

Corvus Corax would engage Magnus in a battle of aetheric energies. Perturabo would vie for dominance in endurance with Mortarion. Fulgrim and Sanguinius would seek eachother out, both desiring to finish the duel started at the eternity gate. Lorgar and Horus would be left to approach the golden throne but there was another group of defenders standing before the steps, Constantin Valdor, Ra Endymion, and Amon Tauromachian stood in opposition to the Aurelian while the Praetorian of stone himself, Rogal Dorn prepared to face the Warmaster. The Duels wrought between Astartes were battled by legends. Astartes such as Sigismund, Abaddon, Lucius, Raldoron, Arkhas Fal and Jubal Khan would battle under the gaze of the Emperor himself.

The duels between the sons of the Emperor would clash within the chamber as a cacophony of martial prowess and emotions. The duel between Corax and Magnus was the shortest, not even the powers of the changer of ways could defeat the most psychically gifted of the primarchs, made even more powerful by his exposure to the Emperor and the webway. Corvus, despite his blessings from the lord of sorcery and change, could not stand against the cyclops for long and was banished into the warp.

Perturabo would release all of his fury on Mortarion, disgusted at what his Brother had become, the two brothers would abandon all finesse in favor of clashing their weapons against each other hoping to use their strength and sheer power to dominate the other, eventually Mortarion's endurance, increased by the blessings of Nurgle would see him prevail and break through the guard of the Iron Praetorian, Mortarion would send the killing blow would sweeping towards Perturabo, intent on bisecting the IV son of the Emperor, instead however he would find the Blade of Ahn-Nunura blocking his strike, together Magnus and Perurabo attempted to banish their twisted brother, but his resistance to sorcery, granted by the god of plagues allowed Mortarion to stand against the force of both of his brothers for a time.

Fulgrim and Sanguinius would fight with perfect finesse as the Great Angel would use The Blade Encarmine with both hands as his spear had been lost in his former battle with the Gorgon, Fulgrim wielded both Fireblade and Forgebreaker intending to kill the one who had murdered his closest brother. Their clash was a battle of speed with both trying to land a killing blow.

The custodians assigned with the duty of holding off Lorgar rushed the primarch together intent on landing multiple blows on the traitor primarch. Lorgar would be able to fend off the numerous golden armored warriors, but it soon became clear that the custodians had the edge in skill and Lorgar gave up any intention of assisting Horus in his fight with Dorn instead hoping to kill the captain general of the Adeptus Custodes.

Horus would clash with Dorn in front of the Golden Throne, trying to turn the stalwart primarch of the Imperial Fists to his side, however Dorn had not gained the title of Unyielding One for nothing and refused to even acknowledge the words of his brother as anything other than the false promises of a damned soul. Dorn would fight with all the skill befitting of a loyal son of the emperor however eventually the chaotic power of the Warmaster would overwhelm even him and it was under the gaze of the Emperor of mankind, upon the world that he had labored to build up that Rogal Dorn, seventh son of the Emperor, Praetorian of Stone and Unyielding One would fall, impaled through his chest upon the Warmasters Talon.

At the death of Dorn the traitor forces would go into a victorious frenzy, intent on capitalizing on the momentary lapse in the loyalist morale. They would miscalculate the depths of fury bound in the normally stoic Imperial Fists. First Captain Sigismund would rally his warriors, and, in a display of bladework not seen since, would cut off the arm of Abaddon and use he momentum gained from the strike to cut across the traitor First Captain's face, taking an eye and leaving a scar from forehead to chin upon the face of Abaddon. The Lord of the Templars would be prevented from killing his foe however, by the intervention of the Justaerin Terminators.

That day the first company of Sons of Horus would be wiped out by the Fury of the Templar Brethren. At the sight of the death of his closest brother Perturabo would dismiss Magnus to help Fulgrim against the Fallen Angel and would finish off the wounded Mortarion using a series of lightning fast strikes that would leave the Daemon form of the Pale King crippled, the Iron Praetorian would not gloat or deliver a speech instead he would remain silent as he raised Dawnbringer bringing down upon the broken form of Mortarion and sending him screaming back through a warp tear, the IV son would intend to help his father but would be prevented by Typhus who would channel the immense warp energy of the banishment of Mortarion to summon three greater daemons of Nurgle directly into the throne room, Perturabo would be forced to fight the Neverborn even as his Father and brothers fought their own battles.

Sangunius had long been accepted as the most martially skilled primarchs, and now with the blessings of Slaanesh bestowed upon him he was able to fight against two of his brothers, for a time. Horus and the Emperor would clash in a brutal battle where both would wound the other until the emperor was forced to break away in order to save Malcador from traitor forces. Horus didn't let the opportunity go to waste and would heavily wound the Emperor, cutting off his arm with his Lightning Talons and caving in the chest of his father with Worldbreaker.

The Emperor, realizing that there was nothing that could be done for his wayward son, and realizing that Horus was truly lost to Chaos, fired a massive beam of energy, obliterating Horus in both body and soul. The traitor forces were stunned at the death of their leader, and in the face of renewed loyalist fury, broke. Lorgar would open a warp tear allowing himself and many traitor champions and astartes to retreat. Sanguinius would, for a time, fend off the three remaining loyalist Primarchs but would be forced to retreat to avoid banishment. Omegon would return from his duel with Alpharius, wounded but triumphant, holding the pale spear, he would reveal however that he had been unable to kill his brother due to desiring to help the Emperor in the final battle against Horus.

At the death of the Warmaster, Traitor forces fled from Terra, and across the galaxy, with most of the traitors legions intending on reaching either the Eye of Terror or Corrupted Ultramar.

The Scouring

Thousands of traitors were caught out by the arriving I, VI and VIII and slaughtered. The leaders of the traitors were unable to rally a significant or coherent force to counter the 3 loyal forces. Each primarch and leader of traitors led their forces and legions in different areas, the wounded Abbadon led the Sons of Horus to the eye of Terror in a desire to escape the Imperium, and take complete control of the XVI legion.

The White Scars would Fracture into multiple warbands after the death of their primarch and the Warmaster, using their supreme speed to outrun most imperial forces.

The Blood Angels would perform a retreat that took them across the paths of dozens of undefended worlds, allowing them to claim billions of slaves and sacrifices.

Lorgar would lead his legion to Colchis in an effort to strip the world of valuables then intend to depart to the Eye of Terror.

The broken Salamanders would be led to a deathworld near the eye of terror by Ignatius Numeon and find a regenerated Vulkan awaiting his legion in all his terrifying glory, somehow revived from being completely atomized by Curze. The black Dragon intended to lead his legion on a raiding crusade across the imperium in a path to the Eye Of Terror hoping to catch undefended worlds by surprise, and reclaim some power for his legion.

Nykona Sharrowkyn led the Raven Guard towards the callings of their master in the warp. Alpharius took his forces and retreated towards unknown space, the only significant force of traitors to retreat to an area not corrupted by chaos.

Typhus would perform a schism within the Death Guard taking those loyal to him, towards an area of the eye that he intended to rule over, while leaving those loyal to Mortarion to fend for themselves.

Guilliman would retreat towards Ultramar with the entirety of his legion.

The World Eaters, held together only by Kharn would retreat towards the Eye but often be forced to descend on imperial worlds to sate the nails and Khorne.

While the Traitors retreated from the Sol System, the Loyal Primarchs and legions held a council on Terra. During this council each legion was assigned what to do against the retreating traitor forces. Omegon used his few remaining agents within the XX legion to pinpoint their location, Leman Russ and the space wolves were sent after them. The majority of the Unforgiven, led by Garviel Loken, pursued Abaddon and the Sons of Horus. Fulgrim and Omegon would bait Guilliman into a trap upon the world of Eskrador near the edge of the Ruinstorm. Konrad would personally go after Lorgar while the Lion chased down the Blood Angels.

Leman and the Space Wolves would engage in a lengthy battle, that would become known as the second battle of Alaxxes, for days the 2 legions would viciously fight in the void with thousands dying on both sides, the Alpha legion was able to escape Terra without many loses and showed that strength against the executioners and left the second battle of Alaxxes damaged but intact. It was said that Russ boarded Apharius's flagship but was unable to kill the XX primarch.

Konrad would engage Lorgar and banish him to the warp upon the sands of Colchis, while his legion butchered the surprised word bearers. Still their sorceries of chaos would be fueled by the power of the sacrifice of nearly every citizen on turning it into a daemon world. The Night lords would be unable to run down the XVII and instead remain to exterminatus the world.

The unforgiven would be unable to catch Abaddon but would destroy dozens of Sons of Horus vessels during their retreat from the galaxy

Fulgrim and Omegon would take on the Ultramarines upon Eskrador, it was here that Omegon would fake his death at the hands of Guilliman, a plan known only to a precious few within the imperium. After Omegon fell Fulgrim would engage and wound Guilliman and push back the XIII legion.

The Lion would unleash forbidden weaponry on the depraved blood angels and kill many, but ultimately they would retreat through a warp tear reeking of corruption, one which the Lion refused to go through.

Dozens of other actions took place throughout the scouring, but the traitors were able to eventually retreat from the known galaxy and take up residence in the eye of terror.

After the events of the scouring were completed the loyal Primarchs would disappear one by one, the last to go would be Perturabo who left the imperium with the chaotic warp storms contained in the Iron Cages.

The time now is the 41st millennium and both Xenos and Chaos crash against the borders of imperium. The light of the domain of the Emperor of mankind is flickering against the darkness of the galaxy.

AN:

I know that this story seemed a bit all over the place and vague, but I do hope to clear up some confusion and go into more detail within the Index Astartes Chapters. I also apologize to those that wished I would have put in other Legion rivalries, initially I did plan to include the White Scars and Death Guard to be on the side of the loyalists but didn't want to have the Loyal legions outnumber the traitors. I also know a lot of people will be upset with my omission of the traditional Istvaan 5 battle. The reason I didn't include it was because I don't like that 3 legions and at least 1 primarch are made somewhat irrelevant in one battle. I know that it's a main part of the heresy but do believe that the story explains why there isn't a dropsite massacre. I am very excited to write the indexes, these will likely take me a long time as I am focusing on school.