The Horusian Heresy
"What madness is this? What insanity drew Horus to this betrayal nay this Heresy?" Quote attributed to Fulgrim Primarch of the Emperors children.
"Father… I will avenge Thee. I will avenge my Brothers and I will avenge the Imperium." Leman Russ at the end of the Terran Campaign.
The Great Crusade
The Great Crusade an age of mankind, strength, and hope. It seemed that mankind could do anything following the unification of Terra by the Emperor of Mankind. The Emperors quick expansion would be rewarded by the discovery of one of his sons Horus Lupercal on the world of Cthonia. For thirty years only Horus and the Emperor fought together then anther Primarch was found Leman Russ of the Space Wolves Legion. Slowly more Primarchs were discovered and along with them Horus's discontent grew.
Finally, the greatest challenge of the Great Crusade was reached the Ork Empire of Ullanor. The long and gruelling campaign would end with Horus Lupercal eviscerating the Ork warboss at the very end of the campaign. The end of the Campaign would end with the Ullanor triumph wherein elements from Sixteen legions and eleven Primarchs, alongside forces from every Imperial military branch would show the Imperium's eternal strength. Then word came from Caliban.
Luther's Rebellion
"For Caliban. For Freedom" Battle cry of the Caliban Independents
"You call me a traitor Lion; you are the traitor you have betrayed Caliban your homeworld. I once called you brother no more. For Calib…" Last words of Luther.
Luther a name damned in both the halls of Terra and the Eye of Terror. What drove one of the greatest of Dark Angels to twice damned betrayal, was never discovered and it never will be. Three legions would be ordered to assault Caliban, The Space Wolves, The Dark Angels and the Iron Warriors alongside a force of custodes dispatched by the Emperor despite Lion El'jonson's protests that his legion could defeat the rebels without aid. However, at the time an VIII legion task force was nearby led by none other than the Night Haunter himself Konrad Curze, the slaughter of Caliban was about to begin.
The defences of Caliban would be battered aside as led by the Perturabo who had designed half the defences the Iron Warriors were able to clear a path through the orbital emplacements quicker than any other save Dorn. The Dark Angels were the first to land upon the soil of Caliban followed shortly after by the Space Wolves and Custodes El'jonson would lead the charge through his treacherous gene-sons while the Space wolves and custodes would aid him in the vanguard. The Iron Warriors fortified the landing zones and the Night Lords hunted.
Many of the citizens of Caliban were neutral in this great conflict with the knowledge that the lifestyle would not change either way. That did not matter to the Night Lords they were guilty of betraying the Imperium and they would be punished for it. The population was slaughtered with the skins of the citizens adorning the landscape of Caliban. A simple message from a newly landing Space Wolf would damn the Night Haunter in this campaign and forevermore. Leman Russ would inform his brother of the atrocities that the Night Lords were committing to the civilian populace El'jonson would fly into a rage and swept back to deal with his genocidal brother. El'jonson would find Curze in a house filled with flayed corpses El'jonson would punch Curze in the face starting a duel that would end with Russ and Pertarubo forcing them apart El'jonson was on the verge of banishing Curze and his legion form Caliban when word came Luther had entered the field.
The counterattack led by Luther pushed the Loyalists back their knowledge that they would die no matter what gave them strength. The attack forced El'jonson to return to the front Lines where he would lead the charge to kill Luther. El'jonson would find Luther tearing his way through the loyalist Dark Angels. The duel began with a question as El'jonson tried to understand the reasoning behind the betrayal and the causing of the revolt Luther would explain his reasoning then the fight began it would last for two blows Luther attacked and El'jonson punched him death crushing his skull in a single blow. With Luthers death the traitor Dark Angels broke. The loyalists stormed across the planet slaughtering every traitor they could find or in the Night Lords case anyone not confirmed loyalist. Luther's Rebellion was over at a horrific cost. At that moment a message arrived from Ullanor in two parts one for El'jonson alone the general message was that Horus had been declared Warmaster and that the Emperor was returning to Terra none but El'jonson know what his message contained.
As the Imperial forces withdrew from Caliban El'jonson withdrew to his personal chambers where he would brood for a year and then Lorgar arrived. For three weeks he would talk with El'Jonson but when he departed, he bore a smile for another of his brothers had fallen to Chaos Undivided. The great betrayal grew near.
The Fall of the Warmaster
"Horus why Horus? He is my closest brother, my light in the darkness, but what does the light attract?" Mortarion Primarch of the Death Guard
"Praise Nurgle. Let the rot flow." Last words of Eugen Temba
The revolt of Davin was an incredibly minor event in the Great Crusade a feral world revolting against the Imperium would usually just mean that the nearest Imperial army unit would get some practise against moving targets and nothing more but Davin was special Davin's governor was Eugen Temba a man who had been granted the title directly from Horus Lupercal. Horus was Furious he would sweep back to Davin and stormed the planet. He led the first wave alongside four-hundred Luna wolves. Eugen Temba would lead the counterattack his bloated form showing his fall to Nurgle the god of rot and disease. As he marched forward the blade, he wielded tore through the Luna Wolves lines until he reached Horus by then he already incredibly wounded and was clearly dying, even still he managed to wound Horus with his blade, he would be killed immediately afterwards. But it was too late the rot had set in.
Horus would slowly waste away no matter what the apothecaries of the Luna Wolves tried Horus still looked upon the verge of death. Then Erebus of the Word Bearers appeared and offered aid claiming that he knew of a medic on Davin who could heal Horus desperate the Mournival agreed despite the objections of one Garviel Loken. Horus would be healed but would always bear the mark of Temba's treachery. He may have been cured of his physical ills, but he had lost his soul to the Dark Powers.
The beginning of the Horusian Heresy
"Death to the False Emperor! Death!" The rallying cry of the traitor forces.
"I cannot promise victory, I cannot promise survival I can promise that we will drown Guilliman in the corpses of those traitors for the Emperor! The true Emperor!" Mortation Primarch of the Death Guard at Isstvan V
Ten years to the day of the Davin Revolt anther planetary governor spat on his oaths to the Imperium and raised his flag in rebellion Baron Vardus Praal governor of Isstvan III seceded from the Imperium Warmaster Horus decided that he would make an example of Isstvan III and show the wrath of the Imperium upon the traitor a wrath that would be directed towards himself not long after.
Horus would order the World Eaters and Iron hands alongside his own newly renamed Sons of Horus to the Isstvan system to crush this revolt. As the fleets of three legions gathered around the traitorous world strange orders were given for individual squads and sometimes singular Astartes were ordered to deploy upon Isstvan III as the selected Astartes gathered in the deployment bays secret missiles were placed in missile silos in preparation.
As the drop pods were launched from the warships orbiting the planet a conference was taking place consisting of the senior leadership of the Legions that were not on Isstvan III. The records of the meeting were smuggled out by some Imperial loyalists in the third year of the heresy. The meeting uncovered the level of planning inherent in the operations that dominated the very beginning of the heresy. The fact that Horus even relied on Angron and the World eaters for vaguely important tasks that did not involve simple murder is laughed in the highest circles in the Imperium. But the plan would succeed and the words of Khârn would go down in infamy "Death to the False Emperor".
As the Astartes on the planet struggled and died in the face of the defenders who had the blessings of Slaanesh flowing through their body. The missile tubes were prepared and then a salvo of drop pods launched from The Conqueror the flagship of the World Eaters as Angron entered the fray. The traitor World Eaters slammed into their unlucky brethren. Their Bloodlust being unmatched on the planet the traitor legions then decided to launch their assault alongside the World Eaters. As the drop pods rained down and Loyalists were slowly hacked down. An order to withdrew to the secured bunkers was given across the loyalist Vox. Soon the Bunkers were filled to the brim with Astartes as those who could enter died on the defences. Then a direct order came from Horus to withdraw and most of the traitor marines did abandoning the planet to the few remaining warsingers. Then the virus bombs were launched.
Isstvan III died and Horus declared war upon the Imperium orbiting its dead mass. The emperor would order six legions to crush the revolt in Isstvan the Death Guard, Emperors Children, Salamanders, Ultramarines, Word Bearers and Raven Guard legions were ordered to the Isstvan system with command being given to Roboute Guilliman. The known traitors had entrenched themselves on the world of Isstvan V, there they stood waiting for the Emperor's wrath. The first assault would be launched by the third, fourteenth and eighteenth legions with the thirteenth, seventeenth and nineteenth legion comprising the second wave. The first wave managed to secure their landing ground and launched an assault upon the traitor lines. The First wave managed to do considerable damage with Angron himself being needed to throw back Vulkan, Mortarion and Fulgrim at one point. Slowly the first wave withdrew waiting for the second as the second wave landing the first wave could be seen relaxing and then the second wave opened fire on the first wave. The loyalists were slaughtered and then Ferrus Manus charged forward he moved quickly and Fulgrim charged out to meet him Fireblade crashed against Forgebreaker thrice before Mortartion's manreaper slashed Ferrus Manus across the back allowing Fulgrim to decapitate Ferrus Manus his greatest friend and closest brother.
The loyalists managed to fight their way out of the killing fields of Isstvan V and fled bringing with them a terrible news war had begun the galaxy was in flames the Horusian Heresy had begun. The long flight across the Imperium had begun. As the fields cooled Horus stood triumphant alongside his brothers the Galaxy would drown in blood.
The Galaxy Burning: From Isstvan to Terra
"Let Prospero Burn" Jaghatai Khan daemon Primarch of Tzeentch
"Konrad your entire life you have been a monster, but you forget what I am. I am the one who hunts the monsters." Leman Russ before killing Konrad Curze at the battle of Krieg
For the eight years that the Horusian Heresy waged from the blood soaked Isstvan system to the grinding Terran campaign. The slaughter rose from the Night Hunters rampage across the Mechanicus, the White Scars assault of Prospero, the battle of Krieg where the second Primarch was killed in the heresy, the four battles of Fenris, the assaults on the Phalanx, the exterminatus of Chemos, Operation Scouring and many more.
The legion once known as the Raven Guard has a long and brutal history prior to the heresy their birth on the moon of deliverance showed Corax's care for those were enslaved or oppressed. That love would be horrifically warped by Slaanesh. During the Heresy they were renamed the Night Hunters and launched on a massive campaign against the Adeptus Mechanicus as Corax saw the vague similarities between them and the tech-guilds that had enslaved him in his youth. The Forge worlds that had pledged allegiance to Horus, this would cause a hand full of Forge worlds to betray the Emperor and stand with Horus. The campaign represented the corruption of the legion itself with slowly but surely the Slaaneshi corruption becoming more evident as they slowly lost their definition of oppression and became focused more and more upon freedom and the destruction of oppression.
The White Scars fall to chaos was one of the most efficient of the Horusian Heresy the subversion of the superstition of the Chorgis born Astartes was an act of mastery by Tzeentch. The slow creation of distrust between the White Scars and the Thousand Sons led to the brutal decision at Neika to ban all pyskers from the Legiones Astartes destroyed ant hope that Magnus might sway JaghataiKhan to the loyalist's side died that day. The grand irony is that the White Scars Stormseers fell to Chaos and corrupted the Khan along with them. The assault on Prospero was the decision undertaken by Horus to crush the most psychically dangerous Loyal Legion. The ascension of JaghataiKhan would be on the ash strewn plaza of Tizca where he would sacrifice 999 Astartes to Tzeentch this allowed him to not only ascend but to destroy the wards that were surrounding the Emperor of Mankind's great work removing from action until Terra. The planet would be abandoned by the Thousand Sons as the White Scars ran rampart over the cities.
Krieg one of the most spiritually important Worlds in the Imperium for it was here that the Night Haunter was killed by Leman Russ in the name of the Emperor. The Night Lords assault was senseless with nothing more sadism determining the target, they could not have chosen a worse one. The main fleet of the Space Wolves Legion was tracking their wayward brothers and translated into the system as the Night Lords began to land. Their fleet was entirely concentrated on the planet below and was entirely unaware to their doom bearing down on them. The Hrafnkel was the first to open fire targeting the Nightfall. The Glorina class warship was horrifically damaged with entire compartments opened to the void the entire Space Wolves fleet was focusing on the ship the ship's spine broke after the third salvo the corpse of the great ship hang over Krieg as the Night Lords ships were hammered and routed from orbit soon the Space Wolves Fleet hung over Krieg then the drop pods were launched. The Night Lords were stuck besieging the Hives of the planet and thus were broken against the walls of the Hive Konrad Curze would lead the counterattack and be slaughtered. He was never the greatest of fighters in the brotherhood of Primarchs and compared to Leman Russ The Emperor's Executioner he was nothing. He would be killed, and his left pauldron torn off to prove that he was dead starting a tradition that continues to this day.
There would be other battles throughout the heresy as the ten-year long war slaughter millions but for most of the Heresy the main conflict was around Horus's push to Terra. The use of Custodes and the fortifications of Rogal Dorn and Perturabo ground down the traitor forces all leading up to a single place Terra.
The Terran Campaign: Blood and Shadow
"I am sorry Sanguinius and Perturabo you shall live forevermore in mankind's memory but now I must leave you." The last words of the Emperor of Mankind before being placed upon the Golden Throne.
"Outnumbered 400 to one surrounded on all sides by Ultramarines and Angron himself coming to deal with me. I feel absolutely confident. For the Allfather!" Leman Russ at the battle of the Lion Gate.
Terra birthplace of humanity, the fulcrum upon which the Imperium lay if Terra fell Horus would dominate mankind and damn them to the Chaos Gods. Thus, most of the traitor force would focus upon taking Terra and destroying the remaining Imperial forces. The majority of eight legions focused upon the Imperial place against them stood the Iron Warriors, Space Wolves, Imperial Fists and the Blood Angels stood in the imperial Place against the traitors. They would fight bleed and die against the hosts of Chaos and they would stand victorious at the end.
The Solar campaign while tied to the Terran campaign was a very different beast with mighty fleets destroying each other across the orbits of mankind's cradle. The traitor's barley won and even during the Terran assault the traitor fleet was attacked by the loyalists. With the Phalanx despite the damage it gained from the battle with the Ultramarines, it still managed to tear through the fleet with the Macragge's Honour being destroyed and Roboute Guilliman was forced to withdraw to the Vengeful Spirit. However, no matter what the Imperial fleet did the damage was not enough for the traitors to withdraw from the Sol system.
The assault upon the Imperial Palace was the bloodiest battle in the Horusian Heresy with three Primarchs dying during the battle. The assault would start at the Helios Gate led by Lion El'jonson against them stood the joint fortifications of Perturabo and Rogal Dorn and Sanguinius himself. The Dark Angels assault led by the newly ascended Lion El'jonson was brutal with the mutation of the legion increasing their effectiveness with the vast majority of the legion slowly becoming mutated hulks that tore through the defenders in the name of the Chaos Gods. Then Sanguinius arrived he personally broke the attackers and slaughtered the leading forces of the legion. To which the Lion himself came to deal with, his ascended form sending terror into the heart of the Legiones Astartes his gaunt winged form with a lion head routing the Imperial Army forces, until he reached Sanguinius the first blow by the Lion was using his new metal wings to attack his fellow angel. The duel lasted for four hours until Sanguinius rammed the Blade Encarmine through the armpit of the Lion banishing him at the price of his own life as Lion El'jonson stabbed him through both hearts. The corpse of Sanguinius became a brutal focus point as every Blood Angel nearby attacked the Dark Angels with unrestrained savagery the birth of the Black Rage. Helios Gate would fall three days later but it would be seared into the heart of the Dark Angels as the greatest failure of their legion.
The next battle was the assault on the Lion Gate where Leman Russ held the defences against him the bitter command of Roboute Guilliman wherein thousands of Ultramarines would be launched at the defences with a single defining goal of just grinding down the defenders with Mortartion's remark from Isstvan V nearly being fulfilled with the sheer number of dead burying any normal human beneath its height. Leman Russ would lead a counterattack tearing his way into the Ultramarines assaulting his position. He would kill well over a thousand Ultramarines despite the incredible resilience of the Nurgle blessed legion. As the Ultramarines started to grind down the Space Wolves that Russ had taken with him in his headlong charge. A decision was made to send Angron down to deal with Russ as the chosen of Khorne should be able to deal with his Fenrisian brother. He wasn't Russ broke both of his chainaxes and then broke his back across his knee. Lion Gate would fall a week later due to the sheer amount of Ultramarines that were throwing themselves against the barriers of the Imperial Palace.
The final Gate was reached at last with the sorcerers of the White Scars looking upon the Eternity gate and shivering as they looked upon the most heavily fortified area on Terra. The assault would be led by the few sons of the Gorgon who still fought with Horus. The roar of artillery would last for two whole months before the first crack appeared on the gate, it would take a further week to break through the gate. Where three Primarchs commanded the defence all three warriors without peer. They would have the enemy corpses pile up and break until the Techmarines of the Imperial Fists and Iron Warriors filled the breach in. Horus would rage for an entire day managing to make Khârn back away from his quarters. Then word arrived that the Thousand Sons, Death Guard, Alpha Legion, Salamanders and Emperors Children were a few days away by warp travel due to the sheer number of casualties that the traitor forces had taken led to Horus taking a wild gamble.
The day before the loyalist reinforcements arrived Horus dropped the shields upon the Vengeful Spirit and thus Pertarubo, Rogal Dorn and the Emperor himself teleported onto the warship. However, they would be separated from each other the first Primarch to find Horus was Pertarubo Horus would attempt to draw him into betrayal towards the Imperium of Man. Pertarubo would refuse and attempt to kill Horus, he would not be even vaguely powerful enough to wound Horus let alone kill him. Pertarubo wold be killed he would be able to damage Horus armour before death but nonetheless he fell. Then the Emperor and Dorn arrived. Dorn would go mad with grief and rage upon seeing the corpse of Perturabo he would go forth and claim Pertarubo's mighty weapon of Forgebreaker, and wielding it alongside his chainsword Storms Teeth he would tear through the traitor marines upon the bridge while his father confronted Horus. Their duel would last for hours with each blow being enough to kill all but Primarchs. But at long last the Emperor lay broken upon the floor of the bridge. As Horus stood triumphant about to claim victory an single mortal stood in front of the Emperor, he would be obliterated by the full force of the Chaos Gods his entire body and soul would be burnt away this showed the Emperor the horror that awaited humanity if Horus stood victorious and unleashed his full force of wrath and fury. Horus would be utterly obliterated his soul out of reach of even the Chaos Gods. Rogal Dorn would return from the depths of rage and return the Emperor to Terra. The Horusian Heresy was over.
Blood and Steel: The aftermath of the Horusian Heresy
"Kill every traitor you come across and stack their corpses to the sky." Rogal Dorn at the slaughter of Medusa.
"Ultramar is closed to us, the spawns of Guilliman have abandoned the cause. We must flee to the eye of Terror." Abaddon heir of Horus and Dark Warmaster.
As the traitor legions broke and fled from Terra, decisions had to be made as one of the few loyal Ultramarines came forward with a suggestion Captain Remus Ventanus believed that the only way to stop something such as the heresy happening again stated that the legion should be broken up into chapters of a thousand marines and the Imperial Army to be broken in two. The Emperors last official act was to declare that the legions would have the option to break off ten thousand Astartes to start a new legion, while the Imperial Army would be broken into the Imperial Guard and the Imperial navy.
Following that decision, the Emperor was interned in the Golden Throne, and the wars of Scouring began.
The Ultramarines would withdraw to Ultramar where Roboute Guilliman would proclaim Imperium Secundus with himself as Emperor as the Heir of Horus, this would be badly taken by the other traitor legions this would not stop them from using Ultarmar as area to get weapons and amour. The Ultramarines themselves gave in further to their patron god of Nurgle as they trudged off to battle.
The Black Legion was the second largest force of traitor marines left following the Terran campaign. Their leader Abaddon would proclaim himself as their Heir of Horus and Dark Warmaster. The Black Legion would carve out an empire for themselves within the Eye of Terror.
The Dark Angels were the third largest force of traitor space marines. They would manage to carve out a Kingdom on the edge of Imperial controlled space with Lion El'jonson ruling from the world of New Caliban. However their would be two major splinter groups from the Dark Angels the Sons of Luther and the Merry Men. The Sons of Luther are a force dedicated to the teachings of the traitor Luther who believe that Caliban is the most important focus of the Dark Angels. The Merry Men are Dark Angels who have abandoned all loyalties besides money and power they act as nothing more then expensive mercenaries.
The Word Bearers would strip Colchis of resources and withdraw to the Ghoul Stars there they would christian a world Sicarius with the capital being declared New Monarchia to honor the people who died to the tyranny of the Emperor. Lorgar would declare the Holy Chaos State of the Ghoul Stars a theocratic state run off the basis of the Book of Lorgar.
The Night Hunters would dissolve into warbands whose aim was officially to liberate the oppressed people of the Imperium, in reality the former Raven Guard tore across space giving into the depraved wishes of their patron Slaanesh. Their last semblance of unity would be destroyed at the battle of Deliverance when Corvus Corax would be banished by Rogal Dorn when he collapsed the Ravenspire upon the newly ascended Daemon Primarch. The survivors form that battle broke and fled across the galaxy, the majority of them would find a home in Ultramar or the Ghoul Stars.
The White Scars were dissolved into nine mighty hosts at the order of Jaghatai Khan with each leader being a mighty sorcerer, the hosts would spread out across the Galaxy raiding and killing across the Imperium with their actions often being nothing more then a step in the grand plan of Tzeentch.
The World Eaters were badly hit by the end of the Horusian Heresy with the forces all trapped on Terra when the loyalist reinforcements arrived they would nearly be wiped if not one Kharn who would lead the blood mad forces to the nearest space port and managed to escape and overtake a few warp capable ships. Their ramshackle fleet would land on a world on the edge of the Eye of Terror where they would be stuck until their father returned with a mighty fleet.
The Iron Hands would be the first legion would be the first legion to lose a Primarch this would drive the legion to bitterness and wrath towards other legions. The surviors of Terra would at first join their brethren at Medusa however the Imperial Fists and Iron Warriors would overrun the planet. The Iron Hands would flee to a Forge World on the edge of the Segmentum Obscurus which they would proclaim as Manusia in honor of their fallen Primarch.
The Night Lords would dissolve into even more warbands then the Night Hunters they would rampage across the Imperium the legion would be devastated as most forces upon both sides of the heresy would consider them valid targets. The few survivors would withdraw to the Eye of Terror and often join the Black Legion.
An age of Blood: The Forty-first millennium
"The Xenos outnumber us, the heretics are everywhere, and the traitors are rising. So, lets fight in the name of the Emperor and Sanguinius." Lord of Blood Dante of the Blood Angels at the battle of Baal.
"We are outnumbered surrounded and running out of supplies well time for us to do what we do best, die fighting. For the Emperor and Imperium." Last words of General Strum as he led the Death Korps of Krieg into combat with the Tau Empire.
The Imperium is surrounded on every side by dangers the traitors are gathering in the Eye of Terror and Ultramar, Orks rampage across the Galaxy, the Tyrranids are consuming the galaxy, the Eldar are slowly gathering to restore their Empire,, on the eastern fringes empires rise. The Emperor stills sits upon the Golden Throne while he could leave the throne he must guard against the assaults of the Chaos Gods. For in the Grim Darkness of the far future there is only war and the laughter of thirsting Gods.
Despite this the Soldiers of the Emperor fight, bleed and die in defense of Humanity. They hold the works of Dorn from the peaceful reaches of Segmentum Solar to the hellscapes of Segmentum Pacificus mankind stands tall against the hordes of enemies that fight for the destruction of the Imperium.