The Fenrisian Heresy
"And the Arch Betrayer led his hordes against the loyal sons of the Emperor. At his side were half of the Astartes legions, twisted beyond recognition into slaves of the warp. Only through pain and the sacrifice of Man's one true lord was the nascent Imperium able to survive. Now on the edge of the 41st millenium, it still stands through the sacrifice of billions of loyal men. The dream of paradise was lost that day and is still wept for by Our Golden Lord, while his Surviving sons battle to keep the last refuge of man from falling."
Pre-Heresy: The Great Crusade
It had begun, The Emperor's grand scheme for humanity. Hundreds of Thousands of Astartes showed the Galaxy of Man's might and took back the lands Humanity lost during the Age of Strife. His angels of death were divided into 20 legions each led by their Primarchs, the Emperor's own sons. They were to be the Spear of humanity, punishing Xenos for the crime of existing and welcoming the lost worlds of humanity back into the Fold.
Behind them were the endless armies of the Imperial Auxiliary and the God-Machines of the Cult Mechanicus. While the Astartes numbered in the Thousands, the Auxiliaries were counted in the Millions, providing support for the Astartes where needed and took planets where Astartes could not be spared. The Legio Titanicus supported the Astartes where resistance was high and proved the worth of the Mechanicum a thousand times over.
Out of the limelight were the Assassins of the Assassin temples, dealing with threats that brute force could not solve. They committed acts of violence and brutality few would even consider, all in the name of the Emperor and Man. While their work was less lauded than that of the other branches of the Imperiums Military, they were no less important.
With such power at its disposal, the Great Crusade hit the galaxy like a hammer. The armies of man reclaimed worlds at astonishing speed and within 200 years the majority of Humanities lost worlds were back in imperial hands. The Age of Strife was over and it was now the age of the Imperium.
Upon Ullanor The Emperor announced his decision to retire from active command of the Great Crusade and handed over command to the Firstborn, Horus of the Luna Wolves. He then took Magnus to with him to Terra to help him with the work ahead.
In hindsight, Ullanor was where it all began breaking apart. While most of the Primarchs either supported their brother or didn't care one way or the other, a few were completely against it. Some like Mortarion merely thought it was not a good idea to deprive the Crusade of its symbol in the Emperor and had their fears assuaged, while others like Russ and Guilliman thought they should be made Warmaster and Horus only received the position because of Nepotism.
Horus was eager to show he would be a worthy Warmaster and the Great Crusade continued onward until another issue cropped up. The use of psychic powers had become prevalent in certain legions and Russ had brought up complaints about it, backed up by Mortarion. While Russ was only one Primarch, The Reaper King commanded much respect among his brothers. Horus decided to host the council of Nikea so that the matter could be decided with The Emperor presiding as judge.
On Nikea, The Emperor heard out both sides arguments. Magnus kept silent for unknown reasons (An act that earned him the respect of Mortarion) despite the outcome being of vast importance to his legion. Mortarion went upon the stage and argued using logic and tales of his time on Barbarus, convincing many of the mortals watching. Kurze then took over and told them all of what he saw (toned down of course). The Primarch of the Night Lords was known for his Powers of Prophecy even then. He didn't make an argument of whether to allow Psykers or not and merely provided information. Kharn of the Sons of Angron took the stage and gave a stellar argument for the use of psykers. With their lack of a Primarch, they made much use of them so that they might reduce their losses. One by one each primarch gave their opinions to the Emperor. All except Russ who said he would keep silent as Magnus was. While this seems like Chivalry, Russ had already fallen to the Lies of chaos and was hoping to profit no matter which side won. If he had argued against the use of psykers he would have lost Magnus as a potential Ally.
After both sides had finished, The Emperor told out his decree. Sorcery was to be banned from the Legions but strictly monitored Librariums of Psykers were allowed. This compromise satisfied both sides (and left no one for The Wolf King to take advantage of). Mortarion requested permission from his father to not have a Librarium and was granted it. The Emperor then requested Rogal Dorn to serve as his praetorian and help fortify Terra. But Dorn in his humility, said he wished to give the position to his most beloved brother, Perturabo of the Iron Warriors. The Iron Warriors had done much work over the Crusade and he wished for them to be honored as he was. The Emperor smiled and accepted his request and Perturabo in turn made a request of Dorn. He asked for a Contingent of Imperial Fists to aid him and identify mistakes that he would not have noticed himself. Dorn agreed and the Brothers embraced.
Horus did not neglect his own duties as a Primarch. He and his Lunar Wolves came across the Interex when they were conquering worlds in their systems. It was amazing to see another major civilization that had not fallen prey to Old Night. The Interex were a predominantly human group with a few xenos taken under their wing, which while against the Emperor's decree, interested Horus. However, while he was negotiating with their leaders he was attacked by an unknown assassin armed with a relic from The Age of Strife stored in one of the Museums of the Interex. It was coated in an unknown toxin that was powerful enough to force Horus into a Coma. Garviel Loken of the Mournival had to physically restrain Ezekyle Abaddon from going into a killing fury upon the people of the Interex, for the evidence made it seem suspicious that the Interex had planned this attack. The fire the Assassin had set to distract them had killed many of the Interex's citizens and they had stolen an Interex ship.
The Raven Guard Aspirant held the blade in his hand. The fools of the Interex had left it almost unguarded. While it appeared as a simple blade, he knew what it was and what it had done. He cracked open a flask and dipped the knife in it. The poison coated it and the weapon was ready. Soon it would be used, and the will of Corax would be done.
One of the Psychically Gifted doctors who was treating Horus identified the toxin as warp tainted. If it wasn't removed, best case scenario it would kill him. It was then that the Mournival was enlightened to Chaos. While the Interex lacked psykers of potency like the Thousand Sons, the ones that they did have were strong enough to suppress it until Imperial Psykers came. Loken sent out an Astropathic message to both Magnus and Lorgar who were known to be experienced in matters relating to the Warp.
Magnus could not come himself because of the Work going on in the Palace, but sent his most favoured son Ahriman. Lorgar's legion was closer and he left it in the care of Erebus while he went to aid his brother. Ahriman and Lorgar arrived and with the aid of the Mournival began curing the Warmaster. Ahriman functioned like a magnifying glass for Lorgars vast psychic powers, focusing them toward freeing Horus. They burst through the Mental Chains covering the soul of Horus. Meanwhile in Realspace, Daemons began appearing, led by the ferocious Skarbrand. They attempted to assault Horus and Lorgar to stop the process while both primarchs were unable to defend themselves. But the Mournival managed to hold them off with the aid of the Strongest of the Interex's psykers until Horus, like the giants of myth, rose from his coma.
One by one they fell. Syrex of the Interex collapsed on the floor bleeding from the nose, mentally overloaded from suppressing Skarbrand's aura. Little Horus Aximand was sent flying into Torgaddon who collapsed from the force of the blow. Loken was on the floor with his legs crushed, still attempting to fire at the Daemon. Abaddon was the last line before he could attack the Primarchs and Ahriman. He knew that he wasn't enough to bring it down but hopefully he could buy enough time for the ritual to finish.
"Skulls and death and blood! FOR KHORNE!" the Daemon mindlessly howled as it charged Abaddon who met it head on, yelling out his own battle cry to give him strength "LUPERCAL!"
Abaddon was knocked back into the wall, his back broken. He could no longer get up so he ineffectually snarled at the Daemon. This was the end and he would go out like a proper son of Chthonia, screaming his rage and defiance at the enemy till the death. But as the Daemon approached to end it, a massive hand grabbed its head and began squeezing. Horus rose to his full height and brought the Bloodthirster closer and said to it "Tell your masters that Humanity will never be its slaves. Tell them that My father comes for them" before crushing its skull in his hand.
After banishing Skarbrand, Horus rushed back to Terra with Lorgar and his own legion, throwing negotiations with the Interex aside. He did however take one of their psykers with him, for he owed the man a blood debt. The warp was heavy in turmoil and by the time they got there, it was too late to warn his father. The Heresy had started.
The Beginning of the End:
Terra was in uproar. News had reached the Emperor that the Wolf King, Leman Russ had rose against The Emperor and his Imperium. He claimed that the Emperor was weakening humanity and had left what was won with warriors blood in the hands of cowardly mortals. He claimed Fenris and all the worlds his wolves had taken as his property, independent of the Imperium. Even worse, Sanguinius, Jaghatai Khan and Lionel Jonson had raised the flag of rebellion alongside him and had purged their ranks of those loyal to the Emperor. Only with the Grace of the Emperor was one ship able to escape. The Battle Barge Victus was filled with as many loyalist astartes as could be saved, led by the Flesh Tearer himself - Nassir Amit. They were the ones who informed The Emperor about their gene-fathers' treacheries.
"Why were we not told of this threat father? If you had informed us then we could have stopped them!" Horus asked in a quiet voice. It seemed almost unreal how so many of his brothers could rebel.
"Because, the very knowledge of their existence is food for them. By not telling you all i hoped to avert this from happening," The Emperor replied. He sounded tired and had a look on his face similar to the one he had on his face when He ordered the destruction of the second and eleventh legions. An expression of immense sadness and the resolve to do what must be done.
"Yet it still happened father," Horus said. Upon hearing this, the Disguise of the ancient warlord that most of humanity saw seemed to fall off and Horus saw the Weary Old man underneath that truly was his father.
It is rumored among the highest of the inquisitor lords that The Firstborn was to be the champion of the Dark Gods in the Materium, but the Intervention of Lorgar and Ahriman put an end to that. But the Gods had plans in case this happened. After much delibration on their end, their eye fell upon Leman of the Russ. While he was not the most popular of the Primarchs, in raw combat power he was almost unmatched. Moreover his own paranoia and pride would make him much easier to corrupt. The Dark Gods fed lies into his ears and stoked his anger about being passed over for Warmaster while feeding his sorrow about the Wulven. They also had their first servant, Corax reveal to him records from the Emperor's creation of the 7th.
Reports also came in that Nocturne had been destroyed. There had been a rebellion and the Word Bearers and Thousand Son troops that were nearby had diverted to aid their cousins. Both they and their cousins in the Salamanders had disappeared along with their Primarch.
While Horus and his sons were needed elsewhere, Lorgar and his could help with the bringing down of the traitor legions. He send word ahead to the closest loyal legions to converge upon the Isstvaan system to punish the Traitors.
Betrayal on the Red Sands:
Of the seven legions who answered the call, first to arrive in the system were The Primarch-less warriors of the Sons of Angron. Their fury at this betrayal was immeasurable. Loyalty to one's brothers was one of the foremost creeds of the Sons of Angrons and the thought of the three primarchs betraying their own infuriated them. But as always they returned to their state of hard earned calmness.
Next to arrive were the Word Bearers. Led by the Herald of Truth, Lorgar, they were ready to show all the price of treachery. Behind them were the glorious Emperor's Children, Stalwart and shining and their closest friends within the legion, the Iron Hands. Guilliman and the Ultramarines were accompanied by their more subtle cousins, Corax of the Raven Guard. Last to arrive were the Shield of Humanity, the Death Guard. Mortarion was beside himself with rage. How was humanity to survive if it couldn't stay united? Unlike the Sons of Angron he had no reason to chain his fury.
A battle plan was formulated. The Emperor's Children, Word Bearers, Sons of Angron and Death Guard would head down to the planet first and the Iron Hands, Raven Guard and Ultramarines would deliver the final blow and support the first 4 legions from behind.
Upon Istvaan the loyalists were astonished at how much the traitors had changed. The noble warriors of the Blood Angels had degenerated into little more than savages. Their fangs were lengthened and claws grown, decapitating their foes and draining blood in the name of Khorne. The Dark Angels cast sorcery upon sorcery invoking the babbling madness of the warp and breaking the minds of those who came too close. Worst of all were the Space Wolves. For once, the Wulven were unleashed where the other legions could see them. They bounded across the battlefield like werewolves of yore, far ahead of the rest of the legions. The (relatively) unmutated Space Wolves were anointed in symbols that burnt the eye to see and much less understand.
Against the sheer force of the traitors, the loyalists could do nothing. They swarmed around Mortarion and Fulgrim who fought back to back and retreated to where they thought they would get support from the other legions.
"This is Lorgar, Primarch of the Word Bearers! Open fire damn you! I order you to open fire on the Spac-"
Lorgar leaped out of the way, his enhanced reflexes saving him as the Ultramarine squad opened fire...at his sons
It was a masterstroke, slaughtering more than half the loyalist troops. They had to evacuate. Suddenly the Night Lords dropped out of the Warp and dropped their marines in. The Traitors felt fear and the Loyalists felt hope that Konrad Curze had foreseen this and came to lend aid to his Loyal Brothers. But it was not to be. The visions of Curze had mislead him. Traitors within his own legion made sure that he did not receive the information about Leman betraying the Emperor and the Dark Gods sent him visions showing the Space Wolves being cut down by furious Emperor's Children and Word Bearers, misleading him into believing that they were the traitors and the Space wolves were loyal. The Night Lords attacked the loyalists calling them out for being traitors (confusing both sides). The Sons of Angron suffered the most from Night Lord attacks.
They had to retreat to the ships. Mortarion, Fulgrim and Lorgar formed an unrelenting spear through the traitors, guiding their sons. Kharn used his unmatched tactical expertise to help coordinate the retreat. But they weren't going to make it. There were simply too many traitors. Then Mortarion told his brothers to go ahead. He would hold off the traitors untill the loyalists boarded and were safe. If anyone else made this offer it would have been madness and foolish but he was the Lord of Death, the Shield of Humanity. It broke his brothers hearts to let him sacrifice himself but they knew it must be done. All of the Death Guard offered to stay back and help their father but Mortarion only allowed half his Deathshroud to stay with him.
Mortarion finally unleashed his long suppressed psychic powers. He knew that he would be dead long before he became corrupted by them. Weapons and flesh disintegrated in his very presence and psychic bolts were nullified. He swept the traitors away with his scythe, Silence, and burned their treasonous hides with his plasma pistol. The Angel of Blood himself could not stand against Mortarion.
Sanguinius was bleeding from a hundred different wounds, He fell before Mortarion on his knees. Mortarion hefted Silence to end it.
"Do you have any last words traitor?" Mortarion spat out. Despite it all, Sanguinius was still his brother. That was worth giving him the time to voice his repentance for betraying their father. Not that it would save him of course.
"Forgive me brother! Corax forced me. H-He surged the Sea so the Crimson took the Gold and it has been gone!" The anti-warp properties of Silence had banished the madness Corax induced upon Sanguinius for the smallest amount of time before it returned and Sanguinius began babbling again.
Mortarion looked down at what his brother had become with disgust. "You were weak brother." He prepared to execute the Angel of Blood before suddenly being tackled from behind by something. When he regained his footing, Sanguinius had been moved and was in the arms of Jaghatai Khan.
Although the Khan and Sanguinius combined their abilities, still they were barely able to escape with their lives. After losing soldier after soldier to Mortarion and his Deathshroud, Leman ordered him to be orbitally bombarded. Mortarion saw the ships charging their cannons and knew it was over. He pressed the teleport homer which teleported his one of his last surviving men into one of the loyalist ships in orbit about to run, after handing Silence to them.
Mortarion bellowed out his fury to the multi-hued skies of Istvaan. He had given his scythe to his First Captain, Typhon before teleporting him away but he was no less deadly. The hum of ship weapons was getting louder and he knew he didn't have much time left. He called out to the Traitors,
"RUSS! HEAR ME YOU THRICE DAMNED BASTARD. I DIE LOYAL TO MY FATHER WHILE YOU WILL DIE LIKE A DOG BY HIS HAND,"
Deep within his ship (for Leman was indeed listening) the Wolf King felt fear in his black heart. He ordered the cannons to be fired.
Standing upon a hill made of his foes bodies, The Lord of Death fell. Daemons scoured the warp for his soul but they found naught but ashes.
The death of Mortarion hit the Loyalists hard. While only Horus could say that he was close with him (for Horus was close with all his brothers), he was still one of the most respected Primarchs, and the most experienced in dealing with threats like these. Horus ordered Dorn back to Terra to help Perturabo with fortifying Terra. They destroyed works of art that had stood for millennia and replaced them with turrets and batteries.
Lorgar and Magnus handled threats immaterial. Magnus channeled Lorgars vast psychic potential and combined it with his own to create a massive ward that covered the entire imperial palace. He then bound 15 of his strongest sons (excluding Ahzek Ahriman) to maintain this so that he could focus his attention upon other matters.
The Advance on Terra:
All knew that Russ would attack Terra eventually. He could take the rest of the Galaxy, the whole universe and if Terra still stood, he wouldn't have won. Only once the Emperor's Laurels rested upon his head and he sat upon the Golden throne, would his victory be complete.
Despite having two primarchs to head the building of defences, there wouldn't be enough time. The traitors smashed through the defences of the worlds on their way. Then the Alpha Legion stepped in. They had done almost nothing throughout the heresy so far, and some said that the Primarchs were deciding which side to fight for. But they were wrong. Alpharius Omegon was merely waiting for the hundred traps he had made to be triggered. All at once, warp drives exploded, gellar fields failed and navigators were slain. Alpha Legion infiltrators all had entered the traitor ships and crippled their advance. The Alpha Legion then engaged the Raven Guard and Night Lords in a battle of wits and stealth, destroying many of the traitor's resources. While it wouldn't stop the traitors, they bought the Imperium much needed time.
Alpharius advised Lorgar to take the Sons of Angron and his own Word Bearers and assault Ultramar while they were still reeling from the thousand treacheries of the Alpha Legion Infiltrators. And Lorgar listened. He took almost the entire warhost of the Word Bearers and led them alongside the Sons on a path to Macragge. However, their plans were revealed to Guilliman by his Dark Patron. He sent his Favoured son, Marius Gage ahead to enact a plan they had devised. With him came a circle Ultramarine sorcerers and multiple ships full of slaves. It is unknown what exactly happened but Gage summoned a Warp Storm all around Ultramar, trapping both legions within.
Horus slammed his fist into the table, cracking its steel surface. He looked up at Alpharius and asked "You said they would be safe. Lorgar is alone in there with only what remains of his Legion and our late brother's. Against all the Ultramarines in Ultramar. Why brother?"
"You know I cannot tell you that Brother. You will not allow it. Trust in Me brother as Magnus does," whispered the Armored Figure who claimed to be Alpharius Omegon. His voice was quiet, like someone who does not want to be heard but the words were clear to all in the room.
The Crimson King spoke up, "I know your plans little snake. Although it breaks my heart to allow them, i know they must be done. For the Imperium," Alpharius knew better than to be offended. His brothers harsh words were only because Magnus had seen the necessity of what he had done. While Magnus's visions were less accurate and more prone to warp corruption than the Acuity, he couldn't deny their potency.
"Fine. Do what you will Alpharius," Horus dismissed them and put his hand in his heads.
With 2 legions trapped and one crippled, Horus was forced to consolidate his forces. He had the outermost planets abandoned and brought to segmentum Solar. Many lives were lost enroute to Sol. But they helped make Sol into a much better fortified system.
Around this time, Lionel Jonson and his Dark Angels headed to their home planet of Caliban. It is unknown what happened but it left Caliban destroyed and the area around it a zone of anti-warp.
Corax undertook a grand ritual upon Istvaan. With a drop of blood from every primarch and a sacrifice of 888 Loyalist Space Marines captured specifically for this purpose, he unleashed a surge of warp energy, aimed at the Emperor. He hoped to weaken the emperor but its effect was much worse. A Primarchs psychic signature is very similar to that of the Emperor, Similar enough to bypass the wards around the Imperial Way and shatter them entirely. Immediately swarms of daemons began attacking through it and the Emperor was occupied for the rest of the heresy fighting off Daemons.
Mars was undergoing its own period of civil war. Led by the dread magos, Zagreus Kane, the traitors were winning. Olympus Mons was the only Loyalist Stronghold remaining. Perturabo had wanted to avoid too many troops to Mars as they were all needed for Terra. But if Mars fell, Terra would be in dire straits so he sent a company of 500 Iron Warriors accompanied by 300 Imperial Fists and a squad of Thousand Sons, all led by Warsmith Kydamor Forrix. They retook the most vital parts of Mars, but the whole planet was still a battlefield so no aid could be expected from it during the siege.
On the way to Terra, Guilliman's forces had run into a fortress planet seemingly commanded by Alpharius himself. With it's proximity to the 500 worlds, it could not be ignored. Guilliman himself went with a quarter of his legion to crush the Hydra once and for all. Eskrador could not stand against such force and fell. Guilliman claimed to have killed Alpharius and desecrated his body in the name of the Changer of Ways, but this wasn't the crippling blow to the Alpha Legion that was expected.
The Siege of Terra:
The Eight Traitor legions had gathered at the edge of Sol. As one they surged forward and smashed through the Praetorians Defences (while taking heavy losses along the way) before swiftly taking every planet in their way until they Hit Terra.
While thousands of ships lay in Orbit, All knew that the real combat would happen on the ground. All the traitor legions descended upon Terra, leaving most of the ships in the hands of mortals. The Space Wolves and White Scars threw themselves against the walls, backed up by the Obliterator virus infected Iron Hands. Through sheer ferocity they broke through the walls 5 different times, repulsed by the defenders inside each time.
The Night Haunter led his legion on a rampage through the hive cities. He had seen what was to come and it had driven him mad. He wanted to put the citizens out of the misery of what was to come. But they did not go down so easy for they had the Aid of the enigmatic Alpha Legion. Traps were set and Ambushes were made. While they did not succeed against the might of an entire legion, they repaid blood for blood.
Corax released his newest pet project. Raptors. Twisted in the mind by the Warp lore used to create them, they were insane beyond even the standards of chaos. This was coupled with a physicality similar to those of the Thunder Warriors of yore. They bounded across the battlefield attacking whatever came in their path be it traitor or Raptors sported mutations similar to those of their father's namesake with black wings and an aura of dread.
The Ultramarines protected the rear of the traitor advance. Long distance was best for their sorceries. They called out the names of Tzeentch while brutally killing any who tried to attempt an attack from the back. Guilliman left lead of the legion to his commanders while he concentrated solely on the battle.
The Dark Angels let loose their daemon-beasts and engines which ran across the battlefield, amongst the Raptors and the Wulven, while the engines bombarded the walls with Warp Shells and Ruinbeams. Their Primarch accompanied Leman, the two of them making a deadly combo as anyone who faced them could attest to.
Despite the forces arrayed against them, the Walls held. The genius of Dorn and Perturabo assured this. Horus coordinated the troops from the inner sanctum and his Mournival relayed his orders while they fought on the frontline. Lorgar cast golden orbs of fire into the traitor ranks while he smashed through them with his mighty mace. While he wasn't the most martial of the primarchs, his zeal and hate more than made up for it. Magnus shielded the Palace from daemonic incursion so the traitors could not call upon their warp allies as easily. The few times he took to the battlefield he was a force of destruction. Towering over the battlefield, surrounded by a hurricane of pure mental force, he obliterated massive swathes of the battlefield.
Fulgrim took to the battlefield the most out of all the primarchs. He was no planner, no psyker nothing. He was humanities champion and he would show these traitors the price of heresy. He threw himself against the traitor legions alongside his sons. They reserved special hate for the Iron Hands and Fulgrim called out for their primarch while he was killing them. Unlike the other Primarchs, Ferrus Manus looked exactly like he did pre-heresy. He apologized to Fulgrim and told him he didn't want any of this. At the sight of his seemingly untainted brother apologizing, Fulgrim's hearts softened. He said that there would still be redemption for him if Manus surrendered and fought for Man instead of Chaos. This was a more innocent time. Manus agreed and the brothers dropped their weapons and embraced. Then Ferrus Manus showed his treachery. Spikes jutted out from his body, Impaling Fulgrim. He was fully in the thrall of Slaanesh and his patron in its "benevolence" gave him complete control over the Obliterator virus his body was infected with it.
At the death of the Phoenician, the defenders fell back. Their hero had fallen. It took all of the Praetorians skill to make sure the walls didn't fall. Even so, they lost vast sections of it and many troops.
Horus himself took to battle the next day. The Firstborn proved to all why he was known as the Master of War. However when he had to confront Sanguinius he faltered. Sanguinius was his closest brother before the Heresy and to see what he had become hurt Horus hard. Sanguinius took advantage of this opening. He kept Horus on the defensive and knocked him unconscious. However before he could end it, The Interex psyker challenged him. While he was no match for Sanguinius, he had still challenged him and Khorne could not let this pass, let alone from a filthy witch. Charged with the blessing of Magnus, he managed to survive for a whole five minutes before being run through by the Blade Encarmine. When Sanguinius turned back to his brother, he had disappeared. Horus had been rescued by his Mournival. However his wounds were grievous and he was unconscious.
Seeing the death of Fulgrim and the near death of his Favoured Son, the Emperor declared no more. He summoned Lorgar down to the Imperial Way and told him to defend it. He then telepathically taught Lorgar everything he needed to know to harness his Psychic powers. For once the vast power of Lorgar (eclipsed only by Magnus) was in full use.
On the Traitor side the Wolf King heard from his allies in the warp that the Word Bearers and the Sons of Angron had escaped from the Ruinstorm and were heading straight to Terra. He also heard about Vulcans Get attacking his ships that were in transit (and attacking imperials as well). Things were looking bad for Russ. He and most of his traitor legions specialized in Hit and run tactics and nomadic shock trooping but he had let them get involved in a siege, the Speciality of both Dorn and Perturabo. In a last bid for victory he took almost all of his Traitors and formed a single company that (while suffering heavy losses) attacked a single part of the Wall, breaching through. But it wasn't so easy. Magnus and Dorn had created a maze that divided the Traitor primarchs. The Khan faced the Stone King, The Gorgon faced the Praetorian and the Blood Angel fought Horus, who had been healed by Lorgar and Magnus. Corax had disappeared from Terra and Kurze was still slaughtering civilians. The Arch-Traitor had been given a trap laden path to the throne (For Magnus knew he would have found his way anyway), which while not enough to kill him, killed all his sons who accompanied him. But within the Throne room, instead of The Emperor, All he found was Magnus. It had been a ruse. His rage was endless and he attacked the wards around the Crimson King.
Magnus stared at Leman with his one good eye. "Why?" he asked, but he already knew the answer.
Leman did not bother to answer. His rage burned hotter and hotter as he pounded upon the Golden wards, his flesh burning and regrowing with each blow. He roared at the Witch who stood in his way of his Vengeance, and his Throne. His hate coalesced into a final blow which shattered the Wards around his claws. The Primarch would have wondered where his fingers went but all that was in his mind was the Hunt and in front of him was the Prey.
Leman shifted into the wolf form that the Gods had gifted him. It was that of a massive wulven with a rune marked hide and obsidian claws that seared through warp magic. He leaped upon Magnus who fought well, worthy of his more martial brothers. His psychic abilities were of almost no help but he held his own. But it couldn't last forever. The Wolf King grabbed the Crimson King and broke his back. He then threw him on the floor to die bleeding out. The ultimate sign of contempt. He let out a howl throughout the palace so that the Emperor could hear him, that he had murdered another of his sons.
The Emperor felt its reverberations and teleported into the Throne room to see the scene of horror in front of him. His beloved Crimson King broken and bloody on the floor and his Failure of a son, mutated into a were-beast of yore that had caused it. He shed a single golden tear and leapt at his once-son. It was a hard fought battle but there was still love for his Leman Russ within his heart. Leman took advantage of this and knocked him down, breaking His bones. He went to finish it but an Imperial Soldier who had been watching this fight distracted him. He fired upon Leman Russ and then in a feat of suicidal bravery charged him with his combat knife in his hand. His name was one that would be sung in the future as the epitome of heroism, Ollanius Pius.
He had his father at his mercy. Now all he had to do was kill him and take his laurels. He approached him...before suddenly getting a las shot in his left eye. While it barely stung the thought of being shot while he had finally one was incomprehensible. He turned to see which hero had done it and saw a simple Imperial Auxiliary with a smoking las gun pointed at him. He let out a great laugh and bellowed out, "You? The Mighty hero who will save my father! Your Emperor is dying, Your shield destroyed on Istvaan and your champion murdered by my brothers hands. Why do you fight? Why do you bother resisting chaos when that is all there is?"
"For Man!" Pius said as he dropped his lasgun and charged the Primarch with his combat knife. Leman grabbed him and swallowed him, crunching his body in between his long sharp fangs.
Upon the floor in front of Leman the Emperor frantically gathered psychic energy while weeping for the Bravery of this one man, this one man who may have saved the Imperium and for the Monster that had once been his son.
His sacrifice bought the Emperor much needed time to gather a psychic lance and obliterate Leman. His destruction of the Wolf King was so thorough that even millennia later, the Dark Gods cannot find his soul. The Emperor saw that he was lost, so rather than attempting to expend his psychic energy healing himself, he sent out a cry to all in the palace that he had mind synced with. Malcador the Sigillite teleported into Throne Room where the Emperor instructed him to heal Magnus. His own wounds were beyond what even the Sigillite could fix. Dorn and Perturabo had beaten off their own opponents and entered the throne room, to see the Sigillite burn himself out, offering the last of his psychic energy to Magnus to heal. The Emperor gave them a final instruction, to place him on the throne. And so they did. Dorn hooked up the numerous wires and tubes that keep our Golden Lord alive to this day and Perturabo turned on a stasis device hidden within the throne for the worst case scenario.
Post Heresy:
After the news that Leman had failed in his attempt to kill the Emperor, the chaos forces retreated to the only safe places available to them, the Eye and the Ruinstorm. They were harassed by both Imperial and Salamander ships the whole time. The Imperium sent out a Vengeance crusade to cleanse all the planets they could of Traitors taint,
Magnus retreated to the Webway gate beneath the Palace, fighting every day to keep the Imperial Dream alive and to keep Daemons from entering the palace. He took half his legion, the other half remained under the control of Ahriman who was given orders to rebuild. Magnus has only left the warp during times of extreme danger for the Imperium like the War of the Beast but never for longer than a day. His power has increased far beyond what it was during the heresy and his mind has been honed by 10 millennia of non stop combat. Every third legionnaire created is given to the Gate where he finds his way to his father through ancient spells Magnus cast upon it before entering. They have their progenoids ritually removed beforehand.
Lorgar led the new ecclesiarchy. He and his sons made sure to keep away from its workings reasoning that humans must lead themselves. After the Reign of Blood they changed their rules to take a closer hand in the working of mortals. Lorgar himself was lost fighting off the hive fleet Jormungandr, diverting it away from the imperium, after being tricked into its path by the Iron Hands. His light is still seen rarely on the edge of the galaxy.
Dorn and Perturabo locked themselves within a room in the Inner Sanctum to protect from any form of harm or corruption. Their only form of contact for the last few millennia has been a Custodian who delivers food and information in and orders out. The Iron Warriors and Imperial Fists man the walls of the Imperium like true brothers in arms. The last time anyone saw the Primarchs was during the War of the Beast.
Corax reappeared on an obscure planet in the Eye of Terror, converted to the cause of Nurgle. He had seen what he had done and realized that he had been played like a fiddle. He went insane with despair, until the Grandfathers voice told him how he could achieve redemption. By bringing down his what remains of his fathers empire and saving humanity by making it embrace the gods. The Grandfather had forgiven him and was the only being in the Universe who would ever do so. So he partook in his love.
The Khan achieved Daemonhood upon the wind swept plains of Chogoris. He had never bothered to retake Chogoris after the Imperials took it, claiming it was no longer of any use to him. He took only his sons and his favoured mortals before leaving. The population of Chogoris were purged and after checking the planet for taint, resettled. But the Khan had been Advised by Genghis to make a grand sacrifice of its population. He led the warhost of the White Scars and took back Chogoris (now renamed Mundus Planus), and had his seers ritually sacrifice its entire population. He received ascension for this and used his new warp powers to plunge it into the warp where it became the White Scars homeplanet once more. He had the whole planet converted into a warship by the Dark Mechanicum. It now wanders the Warp and realspace underneath the command of Jaghatai, who preys upon all the planets in his wake. The White Scars all technically remain under the Command of the Khan but he rarely enforces it, so they wander throughout the galaxy, searching for a good fight and treasure.
The Iron Hands claimed a flesh planet of Nurgle as their own before enacting a grand warp ritual to convert it to Slaanesh. They infected it with a version of the Obliterator virus, bending it to the will of their Primarch. Ferrus Manus stays within his workshop building more and more advanced machines driven by the Will of Slaanesh. He hopes that when he builds the perfect weapon, Slaanesh will finally free him of his pain. The Iron Hands bypass the problem of their infected geneseed by forcing Servitors to grow them. A fledgling Iron Hand is implanted and Infected by the obliterator virus at the same time, to see if his will is strong enough to control it and he becomes one of the Iron Commanders Proteges or if he is good for naught but the rank and file. The Iron Hands are scattered across the eye singing praises to Slaanesh and seeking technology to bring to their primarch.
The Sons of Angrons were commanded by Kharn until he was put into a Dreadnought at the end of the War of the Beast. He sleeps alongside his elder battle brother Lhorke the first. They guard humanity from threats internal with the aid of their Cousins in the Word Bearers. The two legions became very close in the Ruinstorm incident. They are currently the Largest legion, a grand feat for one that has never had a primarch.
Fulgrim may have died but his legion kept his standards. While it is the smallest, each warrior is worth ten others. They are used as a scalpel against Chaos and the Xenos threat, and as a beacon to all Men. They are the Face of the Astartes, and are the heroes of the Common people of the Imperium.
Horus was consumed with regret at his father's fate. If he had been a better son, a better brother, a better warmaster he could have averted this. He refused to stay on Terra, saying that he was unworthy. He took the Luna Wolves and split them in two. Half stayed within the Imperium and were lead by the Mournival. The other half he lead himself, on a Vengeance crusade. He took any marine that would join him and had a massive warhost before leaving imperial boundaries, with the whole of the Interex with him. They crusaded to the edge of the Emperor's Light and beyond. The last anyone heard from Horus was a promise to be back when he was needed.
Curze set his Night Lords free. He told them that even though he was their father, he abandoned command of them. Through the psychic powers of his own Psykers and Gene-wrights from the Dark Mechancium he disabled the Gene links that forced his sons to treat him like a father. From there on the Night Lords forged their own path, and only the truly loyal ones, those who had genuine affection for their insane father rather than Gene enforced love, stayed with the Night Haunter upon his journey. The Night Lords fractured and each one went their own way.
Vulkan stayed separate from both sides. Betrayed by Chaos and Betrayed by the Imperium he realized there was no one he could trust. He took his sons and the Nocturnean survivors, creating his Tribe. They function as pirates, albeit relatively merciful ones. Over time they have gained a following and are paid tribute by all pirates of their claimed territory (excluding the White Scars) and in exchange are not destroyed.
The Dark Angels keep their own company even now. Half of their new home world is covered in daemon-beasts and Xenos surviving in the endless jungles of New Caliban. The other half is where Daemon engines are created for the Long War. Their Daemon Primarch waits to regain his true strength, so that he may finally get what he is owed.
The Ultramarines retreated to Ultramar and fortified it. Their primarch enacts his schemes in the name of the Changer of Ways, while silently fuming about his own lack of psychic powers despite serving the God of Psychic ability. However he more than makes up for this with the sheer amount of schemes.
The Noble Death Guard are called when there is no other option. They spent the first millennium rebuilding their vastly depleted numbers so when they returned to the front, they did it in full power. They offer salvation for the Faithful, Fire for those who are not and Merciful Death for those who cannot be saved. First Captain Typhon led them until his death at the hands of a Great Unclean One while repulsing an invasion of Barbarus.
The Blood Angels fell apart as a legion. The Blood Rage had affected every member of the Blood Angels, from the Primarch to the newest Neophyte. When retreating Khorne demanded blood and skulls for this loss. Almost every member of the Legion responded. Brother killed brother, Serf killed master and Gene-Father killed son. At the end of the Slaughter less than half the Blood Angels remained, and Sanguinius looked upon his work through his Madness and saw it good. At that moment Khorne raised Sanguinius to the Rank of Daemon Primarch.
The Space Wolves have been reunited by the Dreadnought Bjorn the Fellhanded and prepare themselves for crusade after crusade against the Imperium. They are aided by the Black Legion of Bile and the Trinity. Sheer power of desperation has proven to be their greatest ally, as they grew much faster than the other legions and made deals with the devil to consolidate their power.
It is now the beginning of the 41st millennium and dusk is falling upon the Imperium. The Orks are gathering for the WAAAGH! Of the Mad Uruk, The Dark Eldar take slaves in greater and greater numbers leaving whole systems empty of sentient life and the Tyrannid Hive Fleets are approaching in greater and greater number, approaching closer to Terra with each one.
As the End times approach, so does the Threat of the Traitor legions. Reports of Bjorn creating another crusade, united with all the legions are abundant. While the Imperium has fought off many such crusades before, one of this magnitude could shatter the Iron Cages, and finish what Leman Russ started ten millennia ago. The Times of Ending are nigh.