A History of the Imperium and It's People

[Icarus Athrasuriel]

As requested by Lord Commander Erus, I am going to incorporate the History of the Imperium into the Librarium. This is an updated version, in relation to major additions to the Dark Age of Technology, more chronological accuracy and a cut to the Age of Strife passage. If you have comments, please post them on the original thread, which I will also update. I do, however, recommend that you read from this topic, as it will be comment free. Any comments will be moved to the original thread.

Dark Age of Technology
14,000 A.D. - 24,000 A.D.
M15 - M25

Previously, during the Age of Terra, humanity had established colonies out with, but not far from, the Sol System. Spaceships still travelled at sub-light speeds, however, and expansion was hopelessly slow. Despite this, humanity continued to colonise, though inter-planetary trade was non-existent. Journeys from one planet to another could take generations, and items would often arrive centuries after they were needed, and commodities like food were spoiled before arriving on destination.

Finally humanity developed the Warp Drive and Geller Field. Suddenly, hundreds of ships were in production, and mass colonisation quickly followed. One could enter the warp, and leave it somewhere far away in a short space of time. Mankind was all of a sudden connected again, isolated colonies visited by Terrans and soon used the same technology. The Warp drive allowed Man to catch up on technologies from other planets, bringing human society into a new technological peak.

This process of advancement yielded the creation of the Navigators. These human variants had a third eye, referred to as a Warp Eye, which allows them to see into the Warp, and guide their ships. Warp travel became more efficient, quicker and ships could travel further.

Of major importance were also the Standard Template Construction systems. These wondrous devices seem to contain a library and occasionally an entire automatic factory. This enabled the Human colonies to produce whatever was necessary. The STC libraries were said to contain the sum total of all human knowledge, but as the technological level needed by the majority of the population was simple, most STC systems were for producing relatively simple equipment such as threshing machines and airplanes, not warp energy taps or holo fields. Very few examples of schematics for more advanced devices have been found. All these developments enabled Mankind to enter the Golden Age of Mankind. Humanity encountered several Alien-Xenos races like the Orks and the Eldar, and it entered a fierce fight with the first. Human Psykers appeared everywhere but their numbers were small, at first. Later several non-aggression pacts were signed with dozens of Alien-Xenos races.

This Golden Age would not last. Warp travel became increasingly difficult due to the increase in frequency and force of Warp Storms that heralded the impending violent birth of Slaanesh and the Fall of the Eldar. Trade between the Human colonies collapsed. With this relative isolation Abhumans (i.e. new Human sub-races adapted to their environment) like the Ogryns, Ratlings, and Squats developed on several planets. Certain planets, like Terra the ancient homeworld of Mankind, were simply unable to feed their enormous populations. Hunger and starvation followed. The Human psykers were relatively weak and inexperienced and Daemons and other warp entities consumed them, sometimes possessing them for a time. Humanity entered an age of isolation and war and most of its planets where engulfed by civil war, anarchy, and barbarity, leading to the creation of the infamous Titans on Terra. The following time-period is aptly named the Age of Strife.

[Icarus Athrasuriel]

Age of Strife
25,000 A.D. - 28,800 A.D.
M26 - 800.M29

At some point during the 26th millennium, humanity was nearing the end of a period of great success, the so-called "Dark Age of Technology"; this meant that human-kind had reached its technological peak. The "Standard Template Constructs", or STC’s, had been perfected by human scientists and was being used on a large scale. Despite an apparent lack of central authority, humans inhabited vast portions of the galaxy, and their civilization was largely free from difficulties with external factions--namely, other races. This success was about to come to an end.

At that time, the ancient Eldar Empire began its decline; the great success of the advanced Eldar race had led to decadence and hedonism on a great scale. This rampant corruption, which would eventually cause the Chaos God Slaanesh to be born, led to a great increase in Warp Storms. Parts of the galaxy inhabited by humans became isolated by these storms, leading to revolts and civil wars. Many human-inhabited systems also became prey to unfriendly alien forces, such as the Orks.

However, by far the worst event of this period for humanity was the spectacular rise in the occurrence of human mutation, especially the mutation leading to psykers and the psychic powers they wielded. Prior to this, humans had had little experience in dealing with the forces of the warp, and the unexpected appearance of humans who could draw upon its energies led to riots, witch hunts and lynchings. Many psykers themselves were driven insane, either by the great power they suddenly possessed, the fear of persecution, or both.

Many psykers were overwhelmed by Chaos Entities, and were possessed. These possessed psykers, as well as other selfish (or insane) psykers who learned to control their power, would cause even more havoc, leading to mass hysteria and devastating wars. Horrific weapons invented previously during the era of technological achievement were unleashed, turning verdant worlds such as Baal Secundus into barren, irradiated desert planets--or worse.

In a relatively short span of time, the galaxy-spanning human civilization was brought to its knees, and was forced to endure nearly five millennia of terror, war and slavery. Other than tales of great suffering, little information has survived this dark time.

Control of the Sol System shifted constantly between Earth, Luna and Mars during the first half of the Age of Strife. By the 28th Millennium all traces of civilization on Earth were long gone; instead, techno-barbarians battled one another over the scraps of the ancient culture. Little information remains from this dark time, but it is known that tyrants such as Kalagann of Ursh (northern Asia/Russia), Cardinal Tang, and Narthan Dume of the Panpacific Empire ruled during this age. According to the novel Horus Rising by Dan Abnett, Dume was opposed by the Yndonesic Bloc, while the Urals remained a centre of industry.

Mars underwent a very different transformation. After brief anarchy, the tech-priests of the Adeptus Mechanicus emerged victorious over the mutants and unified their homeworld. The tech-priests then visited Earth but were appalled at the destruction there and saw nothing worth saving. Instead, the Martians studied the warp and after many lifetimes learned to detect 'lulls' in the warp storms. At the same time the immense fighting machines known as Titans were created.

For over a thousand years the Cult Mechanicus watched and waited. Whenever a break in the warp storms occurred, an expedition was sent, complete with a full Titan Legion and thousands of servitors and tech-priests. Some of these expeditions were lost in the warp or died on faraway worlds. Others succeeded in establishing so called 'Forge Worlds' - replicas of Mars. Broken messages were transmitted to Mars, but it was not until the time of the Great Crusade that the Forge Worlds and Mars would be reunited.

Eventually, an immensely powerful human leader and psyker known as the Emperor divined that the final birth of Slaanesh was nearing, as well as the effect this birth would have. He made preparations for this galaxy-changing event; he gathered military forces, began his conquest of Earth, and started the processes necessary to create his genetically tailored super-warriors, the Primarchs and then, from the Primarchs' genes, created the Space Marines.

Upon the birth of Slaanesh sometime in the early 31st millennium, the crippling warp storms were swept away (which allowed for easier galactic travel), the Eldar race was nearly annihilated, and the Emperor began to carry out his plans to reunify humankind under his rule. With the Emperor's ascension, the Age of Strife was finally over and a new age had begun. This brief age of conquest, heroism and unity would be known as the Great Crusade, and it would in turn end with the tragedy of the Horus Heresy.


The Age of Strife had a tremendous impact on human civilization. Humanity barely survived the period, and most of the knowledge of the previous golden era was lost, much of it irrevocably; in particular, the loss of the STC system is seen as a serious setback for the advancement of the Imperium. The Adeptus Mechanicus constantly searches for STC technology, and jealously guards what little it finds— in fact, it treats the STC as holy, virtually worshipping it. This focus on re-attaining and worshipping the ancient STC rather than inventing new technology, as well as the centralization of this knowledge in the hands of the Adeptus Mechanicus, has led to a stagnation of Imperial science.

In short, the authoritarian Imperium of Man is the way it is in large part due to the great suffering endured during the Age of Strife.

[Icarus Athrasuriel]

The Great Crusade
28,800 A.D. - 29,000 A.D.
800.M29 - M30

During the Age of Strife the Emperor, who had spent his near-immortal life guiding and influencing mankind, was trapped on Earth, due to Warp Storms. Not content to sit on his laurels, the Emperor spent this time performing biological research on the human genetic code; specifically ones dealing with psychic powers. The result of this work was the creation of 20 highly advanced, genetically engineered superhumans known as the Primarchs. These superhumans, created from the Emperor's own genetic stock, were intended to be the next stage in human evolution.

The powers of Chaos, however, managed to infiltrate the Emperor's secret laboratory. Teleporting the unborn Primarchs away from Earth, the Emperor's plans were in disarray. With no other option, the Emperor used the stored genetic information of the lost Primarchs as a template to create the first prototype supersoldiers later known as Space Marines. Using these first Space Marines, the Emperor united the tribes of Terra under one government. This event was later known as the Unification Wars.

After nearly five millennia, the Warp storms had dissipated from Earth. With the storms gone, and extra planetary travel was again possible, the Emperor began his plans again.

The Emperor's first obstacle was the existence of the empire of the Techpriests of Mars, who had historically been fiercely independent of Earth. Instead of an outright war, the Emperor used the threat of his Space Marines to form an alliance with the Techpriests of the Adeptus Mechanicus on Mars. Despite his disdain for their reliance on religion and cybernetics, the Emperor knew that he would need Mars' factories, mechanical output and ancient technological know-how to unify humanity, and he incorporated them into the Imperium.

The Techpriests of Mars, likewise, saw the Emperor's scientific background as proof that he was the Machine God(or Omnissiah), which their religion had promised would return one day to the Red Planet and offer the way forward for humanity.

Expansion from Earth was slow, primarily due to reasons of manpower. Without the Primarchs, the time required to create a Space Marine was far longer than ideal.
After a time, the Emperor was reunited with one of his Primarchs in the Cthonian system: (Horus). Being the first Primarch (and, in some ways, his first son), Horus and the Emperor formed a truly unique bond, saving one another's' lives on many occasions. With the decreased Space Marine production time, the Great Crusade began picking up steam, with the Emperor's "Pure Human Empire" attracted entire planets to his cause.
After 30 years of successful Crusade, the Emperor discovered another of the Primarchs. Although Horus was pleased at the discovery of one of his brothers, he secretly pledged to always be the Emperor's favourite son, no matter what else.

Over time, all but two of the Primarchs were rediscovered, and given command of the Space Marine legions in which their genetic code was used as a basis. With the rediscovery of the Primarchs, Space Marine production was drastically decreased in time; a Space Marine could be made in as little as a year. This rapid creation, it should be noted, would prove disastrous: mental defects and unique eccentricities crept into the ranks.

As the Imperium grew (and there was a lesser need for a single crusading army), the Primarchs and their Emperor began to grow distant from each other. Isolated from each other, Legions began to conduct acts that would have never been tolerated in the past. For example, the Night Lords and World Eaters Legions began to commit ever-greater atrocities, while the Word Bearers fanatical religious beliefs led to a rift between them and the Emperor.

The Imperial Army, composed entirely of normal human soldiers, provided much-needed manpower for garrison and support duties for the planets conquered by the Crusade. Freed from garrison duties, Space Marines could conquer yet more worlds in a shorter space of time. Many Marines and Guardsmen began speaking only of their loyalty to their Primarch, not their Emperor. Owing to the isolation between Legions and the Emperor, this essentially went unnoticed.

After Horus' successful campaign to destroy the Ork empire of Ullanor, the Emperor declared it the greatest victory of the Imperium to date. Horus' reward was the title of Warmaster, with it the supreme command of the Imperium's Military.
After doing so, the Emperor made it known that he was needed on Terra, where he would begin his next phase for human evolution. Horus was not informed of the Emperor's plans on Terra, and felt troubled by that. To make matters worse, some of his fellow Primarchs did not easily accept Horus' new authority, believing that the Emperor would disband or reduce their own legions to peacekeeping forces.

Horus resented his brother's feelings, which was all the powers of Chaos needed to sow the seeds of dissension into his mind. Soon, the legions rebelled. The Horus Heresy began, as did the fall of Man...

[Icarus Athrasuriel]

The Horus Heresy
30,012 A.D. - 30,014 A.D.
012.M31 - 014.M31

Part 1

During the Great Crusade, it became apparent that the Primarchs were far from the perfect beings they were designed to be. Although each Primarch was physically and mentally godlike, their personalities were each as flawed as those of any mortal. During their upbringing on their respective homeworlds, the Primarchs had to learn humanity from mere humans; for almost all of the Primarchs, this resulted in their harbouring all-too-human flaws (for specific examples, see each Legion's history).

Horus took over command of the Great Crusade, and took up his new duties with earnest dedication. However there was much dissension in the ranks of the Primarchs and other parties. Only a handful of the Primarchs, among them a scheming Lorgar, remained steadfast beside him during this period of dissension. Horus also disagreed with many of the Emperor's new decrees intended to shift the burden of taxation and administration onto the newly-conquered ('compliant') worlds. Even worse, Horus came to believe that he was failing his father, and was deeply wounded that the Emperor had revealed to none of the Primarchs, not even his favoured son, why he had secluded himself upon Terra. These seeds of bitterness, resentment and frustration grew, and would soon bear deadly fruit...

Meanwhile, the Emperor was on Terra organising the infrastructure for his Imperium to function. He created the Council of Terra, a body of bureaucrats and nobles that would implement and administer the new galaxy-wide tax called the Imperial Tithe and other matters of day-to-day law in the Imperium of Man.

The news of the creation of the Council of Terra and its latest bureaucratic edicts angered some of the Primarchs still further. They did not understand why they, the Emperor's greatest champions, who had spilled their blood on a thousand worlds to re-unify all the races of Man, did not have seats on this new Imperial ruling body. The brotherhood of the Primarchs was being shattered bit by bit by this growing resentment and jealousy. Old arguments and differences came to the fore. Horus became ever more distant from the Emperor, seeking only glory for himself and his Legion.

It was on the moon of the world of Davin that Horus' fate was sealed. This was the second time his Legion had been posted to this world; after the previous visit sixty years earlier the Luna Wolves had adopted the native Davinite institution of warrior lodges. Though these lodges had begun as simple fraternities of warriors, their secretive nature handed Lorgar, the Primarch of the Word Bearers Legion, and his First Chaplain Erebus, the tool they needed to manipulate Horus. Lorgar and his Word Bearers came from a world of religious fanaticism, and had long worshipped the Emperor as a living god. The Word Bearers had sought to spread this Cult of the Emperor to every world they added to the Imperium; but the Emperor hated organized religion, blaming it for much of the darkness that had plagued humanity's history. The Emperor forbade any religious worship in his empire, preferring that his subjects instead accept 'Imperial Truth'-- that reason and science alone presented the tools with which to create a better human future.

Lorgar did not suffer the Emperor's harsh reprimand well. Angered that the Emperor would not accept his devotion, Lorgar turned instead to the Ruinous Powers of the Warp - who were all too willing to accept the devotion of one of humanity's Primarchs. Before long the Word Bearers Legion had been almost entirely corrupted by the Chaos Gods, and Lorgar and his First Chaplain were tasked by the Chaos Gods with corrupting all of their fellow Space Marines--starting with the greatest of them all, the Warmaster Horus.

On Davin's moon, which had been corrupted by the forces of the Chaos God Nurgle, Horus was poisoned by a Chaos-tainted blade wielded by the Chaos-corrupted form of the Imperial Army commander the Warmaster had left behind to govern Davin sixty years before. The potent Chaos sorcery of the blade left Horus with a bleeding wound in his shoulder that his legion's apothecaries could not heal, despite the Primarch's superhuman immune system and their own advanced medical technology. Seeing his chance to further the designs of Chaos, Erebus persuaded the Sons of Horus' warrior lodge to allow a group of Davinite shamans - Chaos cultists all - to heal him.

During the rituals, Horus' spirit was transferred into the Warp. There, he bore witness to a terrible vision of the future (which his actions would bring about) - the Imperium as a repressive, violent theocracy, where the Emperor and his Primarchs (but not Horus) were worshipped as divine beings by the masses. The Chaos Gods portrayed themselves as victims of the Emperor's psychic might, and who had no interest in the material world. Horus, already having grown jealous and deeply resentful of his perceived poor treatment at the hands of the Emperor, proved all too willing to accept the Ruinous Powers' false visions. Horus decided that if anyone deserved such an accolade it was he, and not the Emperor, who deserved to be worshipped as a god. The Chaos Gods' pact with Horus was simple: "Give us the Emperor and we will give you the galaxy". He accepted the offer of the Chaos Gods to join their cause: they healed his grievous wound and also gave him access to the powers of the Warp.

Renouncing his oath to the Emperor, Horus led his Legion into worship of the myriad Chaos Gods. He then sought to turn many of his fellow Primarchs to Chaos, and succeeded with Angron of the World Eaters, Fulgrim of the Emperors Children and Mortarion of the Death Guard, who were first of many to follow, along with many regiments of the Imperial Army and several Titan Legions.

Magnus the Red, Primarch of the Thousand Sons Legion, foresaw Horus' actions through his Legion's own use of forbidden psychic sorcery. Magnus then attempted to forewarn the Emperor of the impending betrayal. However, knowing that he would have to find a means of quickly warning the Emperor, and as an act of both desperation and vindication, Magnus used sorcery to send his message to the Emperor. The message penetrated the psychic defences of the Imperial Palace on Terra, shattering all the psychic wards the Emperor had placed on the Palace - including those within his secret project in the Imperial Dungeons: the creation of a warp-gate to invade the Eldar Webway. Refusing to believe that Horus, his most beloved and trusted son would betray him, the Emperor instead perceived the traitor to the Imperium to be Magnus and his Thousand Sons Legion. The Emperor ordered the Primarch Leman Russ to mobilize his Space Wolves Legion and take Magnus into custody; however Horus convinced Russ that Magnus was a traitor and needed to be destroyed.

Much of Horus' success arose from the thorough groundwork he had laid before the opening shots were fired at Istvaan. He had already swayed Angron and Mortarion. Lorgar, who had been responsible for the budding rebellion, was also with Horus. Three of the most loyal Legions, the Dark Angels, Blood Angels and Ultramarines and their Primarchs, were sent on missions far from Terra and Istvaan. The Imperial Fists and White Scars were too close to Terra to be contacted without raising suspicion, though Horus believed - mistakenly - that Jaghatai Khan would ultimately take his side. Shortly before the Dropsite Massacre, Fulgrim also attempted to sway Ferrus Manus to Horus' cause, failed, and barely escaped with his life. Fulgrim promised he would deliver Manus' severed head to Horus in recompense. The Blood Angels were sent to the daemon-infested Signis Cluster and the Ultramarines to Calth, where a large Word Bearer force, under Kor Phaeron, had massed.

Of the other eventual traitors, Night Haunter was due to face disciplinary action from the Emperor; Alpharius had always been closer to Horus; and Perturabo's bitterness towards Rogal Dorn made him an easy target for corruption. The Thousand Sons had never planned to join Horus, but when betrayed by the Emperor and the trap Tzeentch had laid for the Red Sorcerer's legion led them to his side regardless.

[Icarus Athrasuriel]

Part 2

The remaining Legions - the Raven Guard, Salamanders, Iron Hands and Space Wolves- remained staunchly loyal to the Emperor, though all but the Wolves would pay dearly for it in the battles to come. Beyond the Legions, Horus had already swayed Adept Regulus with promises of the STC’s recovered during the war with the Technocratic Brotherhood, delivering Mechanicus support to the Warmaster's forces.

The first sign that Horus and his Legion had turned to Chaos was made evident when Horus virus bombed the rebel world of Istvaan III. The Planetary Governor of Istvaan III had declared his independence from the Imperium, and the Council of Terra charged Horus with the retaking of that world. This order merely furthered Horus' plans. Although the four Legions under his direct command had turned Traitor, there were still some Loyalist elements within the Sons of Horus, World Eaters, and Death Guard; many of these were Terran Space Marines who had been recruited before being reunited with their Primarchs. Horus, under the guise of his orders, amassed his troops in the Istvaan System.

Horus had a plan by which he would destroy all Loyalist elements of the Legions at his command. After a lengthy bombardment, Horus despatched all Loyalist Marines down to the planet, with the pretence of bringing it back into the Imperium. At the moment of victory, however, these Marines were betrayed when virus bombs began to rain down on the planet. However, some Marines loyal to the Emperor had remained onboard their ships, and as Istvaan III died, these soldiers fought desperately to warn their brethren on the surface. Their sacrifice saved many Space Marines, as they were able to take shelter before the virus bombs struck. The population of Istvaan III received no such protection. Sixteen billion people died almost immediately. The psychic shock of so many simultaneous deaths shrieked through the Warp. A contingent of Loyalists led by Captain Garro of the Death Guard escaped the fleet orbiting Istvaan III aboard the damaged vessel called Eisenstein, and fled to Terra to warn the Emperor.

Angron, realising that the virus bombs had not been fully effective against the Loyalist Marines, flew into a rage and hurled himself at the planet with 50 companies of Marines. Horus was furious at Angron for delaying his plans, yet reluctantly reinforced him with troops from the Sons of Horus, the Death Guard, and the Emperor's Children. On Istvaan III, the remaining Loyalists, under the command of Saul Tarvitz, fought bravely against their own traitorous battle-brothers. But their cause was doomed. Soon only a few hundred of them remained until, finally, Horus grew unable to tolerate the delay and forced Angron to withdraw his forces, and ordered a systematic orbital bombardment that killed Istvaan III's last brave survivors.

The seventy Loyalists led by Captain Garro commandeered the Imperial frigate Eisenstein and, evading the forces of Horus, were able to escape from the Istvaan System into the Warp. The Eisenstein was badly damaged during its escape from Istvaan III; all its astropaths were dead, and its lone Navigator was mortally wounded. However, Garro managed to attract the attention of passing Loyalist ships by setting the vessel's Warp engines to self-destruct and ejecting them from the ship. Rogal Dorn's Imperial Fists Legion had been becalmed in the Warp with its fleet for some time, and his Navigators sensed the detonation of the Eisenstein's Warp drives. Making an immediate course for the location of the ship's beacon, Dorn met with Garro, who explained to him all that had happened with the Traitor Legions.

The Eisenstein was able to reach Terra, allowing the loyal Marines to report the extent of the atrocities that had occurred in the Istvaan System. It was said in later millennia that without this warning, the Imperium would have faced even greater difficulties responding to Horus' final moves.

The fate of these seventy Marines is ultimately unknown. Some believe they continued to fight for the Emperor until death claimed them, while others maintain that they were treated as if they were their traitorous brethren, either imprisoned and left to rot, or executed. Others believe that Captain Garro, shocked by the terrible betrayal, became an Apothecary, vowing never to kill again.

Yet there is another story concerning their fate. Malcador the Sigilite had presented eight of the survivors to the Emperor before his departure. These men were gifted psykers, came from the ranks of the Legions that had turned Traitor, and yet maintained both an unbreakable faith in the Emperor and talent for resisting the temptations of Chaos. Many believe these men formed the nucleus of the elite Space Marine Chapter known as the Grey Knights.

[Icarus Athrasuriel]

Part 3

In response to Horus' betrayal, Rogal Dorn ordered seven Space Marine Legions to Horus’ base on the world of Istvaan V to challenge the Warmaster. These Legions were the Iron Hands, Raven Guard, Salamanders, Iron Warriors, Night Lords, Alpha Legion and Word Bearers. Of these, the Night Lords, Alpha Legion, Iron Warriors and Word Bearers had all turned to Chaos.

The three Loyalist Legions, the Iron Hands, Salamanders and Raven Guard, were deployed in the first wave, and attacked the Traitor Marines' forces. As they gained a foothold on the planet, at a heavy cost, Ferrus Manus' obsession with confronting Fulgrim came to the fore and he abandoned his post as Supreme Commander. As the two duelled, Horus committed his hidden reserves, swamping the beleaguered attackers. They fell back towards the drop zone the other four Legions had established, only to be fired on by their 'allies'.

Each Loyalist Legion was almost destroyed in the resulting bloodbath, recorded in Imperial history as the Dropsite Massacre. Ferrus Manus was slain by Fulgrim as all around him his veterans were massacred. Some believe Alpharius, Primarch of the Alpha Legion, planned the operation jointly with Horus. Of the three Legions loyal to the Emperor on Istvaan V, only a handful of survivors escaped, including a critically wounded Primarch Corax of the Raven Guard. The Drop Site Massacre is also the last known place where the Primarch Vulkan of the Salamanders Legion was seen.

(Note: Vulkan was heard from after the end of the Heresy, as, like Russ and Dorn, he is recorded as having objected to the Second Founding. This event is supported by Index Astartes: Black Templars and the Black Templar Codex. The fate of Vulkan is unknown, so some assume the piece concerning the discussion about the Codex Astartes was a mistake in the lore and Vulkan is dead. However, since Index Astartes: Salamanders doesn't mention more, Vulkan's fate remains unknown.)

After the Drop Site Massacre, it became clear that eight of the eighteen Legions had turned to Chaos. Horus openly declared that he would no longer follow the Emperor, believing him to be undeserving of the battles fought in his name, and took leadership of the Traitor Legions, supported by elements of the Imperial Army, a large portion of the Adeptus Mechanicus, and the daemon-spawn of Chaos. Their aim soon became clear: Terra, the heart of the Imperium.

[Icarus Athrasuriel]

Part 4

Rogal Dorn and Malcador the Sigilite, receiving the few survivors from the Dropsite Massacre, became aware of the full implications of their position. Only the Imperial Fists and Imperial Army defended Terra, and those loyal to the Emperor elsewhere were cut off and weakened. He immediately recalled all Imperial forces back to Terra in preparation for Horus' invasion.

The Sons of Horus, the Death Guard, the Emperor's Children, the World Eaters, and elements of the Word Bearers, prepared to rendezvous at Mars. The rest of the Word Bearers Legion was winning the Battle of Calth, and the Blood Angels were still embattled on Signis. The majority of the Imperial Fists' fleet was trapped in an area of the Warp becalmed by the Chaos Gods. Horus assigned the Primarch Perturabo of the Iron Warriors to engage this large force of the Imperial Fists and cripple their fleet.

At this time the Space Wolves had completed the Burning of Prospero, near the Chondax System, where the White Scars Legion was stationed. The Dark Angels were engaged in an unknown campaign on the Eastern Fringe of the galaxy. Suddenly the Alpha Legion's fleet broke from the Warp to engage the Space Wolves forces of the Primarch Leman Russ, hammering his smaller force and forcing Russ to resort to hit and run attacks. The Alpha Legion's Primarch Alpharius also attacked the nearby White Scars piecemeal in order to draw that larger, newly-reinforced Legion into the conflict, and keep them from jumping to Terra to aid in its defence.

The Primarch Jaghatai Khan desperately wished to send his White Scars Legion to aid Russ. And yet as the Traitor Legions' ships attacked, Khan received the order from the Imperial Fists' Primarch Rogal Dorn: return to Terra immediately and regardless of all other considerations. Dorn also ordered Khan to relay the order on to Leman Russ and the Space Wolves, and to add that, should Russ succeed in evading his Alpha Legion attackers, only then should he attempt the Warp jump to Terra. Relaying the message and adding his apology, the Khan and his Legion made the jump to Terra. Leman Russ shrugged, and prepared to meet the Alpha Legion with renewed determination. (With help from an unlikely quarter, the Space Wolves would eventually turn the tables on their attackers and make the Warp jump to Terra.)

As this happened, the Night Lords arrived in the Eastern Fringe of the galaxy to engage the Dark Angels, and Perturabo's armada broke Warp to engage the Imperial Fists' fleet marooned near the Chaos Space Marines' headquarters world of Istvaan V. Surviving the initial thrust of the Iron Warriors' attacks, the Fists' armada held fast and scattered Perturabo's fleet, before Rogal Dorn had his ships make their own Warp jump to Terra.
Meanwhile, in the Signis Cluster, the Blood Angels, granted new and terrible power by a mysterious mass rage (that would resurface again during the Siege of Terra) had triumphed, smashed the Chaos daemon horde they faced asunder before making the Warp jump to Terra.

Similarly at the world of Calth, the Primarch Roboute Guilliman's battered Ultramarines expeditionary force had dug in on the surface, while Roboute himself and the remnants of the Ultramarines' fleet in space began to organise hit-and-run attacks on the lumbering Word Bearers. Surveying the scene on the planet, Guilliman rapidly assessed his ground troop's positions, and began broadcasting clear, concise orders to his men, co-ordinating each pocket of defence. One such pocket, under Brother-Captain Ventanus, organised a breakout and retook Calth's defence lasguns. Ventanus' victory served to even the odds in space, buying time for the vast remainder of the Ultramarines Legion to arrive at Calth and drive off the Traitors. Now reunited, the Ultramarines finally received Malcador's orders, and immediately made the Warp jump to Terra.

As the Warmaster was moving for Terra he received an unexpected communication from the recently betrayed Thousand Sons Primarch Magnus the Red. The Space Wolves had driven the Thousand Sons from Prospero. Magnus pledged his allegiance and the allegiance of the Thousand Sons Legion to Horus and the Chaos Gods in retaliation against the Emperor for this betrayal. The Thousand Sons were en route to Terra where they would link up with Horus' forces. Of the nine remaining Loyalist Space Marines Legions, only the White Scars and Blood Angels were able to join Rogal Dorn and his Imperial Fists in the defence of Terra. Three entire Titan Legions and close to two million soldiers of the Imperial Army stood alongside them.

[Icarus Athrasuriel]

Part 5

The besiegers forced the defenders back to the very walls of the Imperial Palace, where the assault slowed. Around the walls of the Imperial Palace men died in their thousands, clearing enemy troops from the walls only to find twice as many charging forwards.

The defenders' resolve was tested sorely as they beheld their enemy. Daemons, superhuman Chaos Space Marines, and Traitor Imperial Army; all men who had once been their greatest allies. In the besiegers, the defenders beheld a twisted mirror vision of themselves, seeing the darkest, corrupted traits of humanity staring back at them, a foreshadowing of what would befall the Imperium if Chaos triumphed over the Emperor.

Angron, now a daemon prince, came forth and demanded that the Loyalists surrender. They were cut off, he said, outnumbered, and defending a ruler unworthy of their loyalty. It was the beginning of the darkest days for the defenders; many would have given up then were it not for the presence of the angel Primarch Sanguinius, winged leader of the Blood Angels. The two Primarchs gazed at each other, possibly communicating by telepathy. Eventually Angron withdrew, telling his forces that there would be no surrender.

The siege began again, in earnest. Each Imperial defender knew he was already dead, that it was only a matter of how many Traitors would go to their graves alongside them. Three times the hordes of Chaos scaled the walls, and three times they were beaten off with savage tenacity by Sanguinius and his Blood Angels. Outside the walls, the defenders led by Jaghatai Khan tried to draw the main body of the besieger's army away from the Palace, each time meeting with failure. Soon the outnumbered defenders were pushed back into the maze of corridors and bulwarks within the Palace's very walls. Frustrated with his army's slow progress, Horus ordered the Fire Wasps Traitor Titan Legion to demolish entire sections of the wall. Despite grievous losses, the Titans gouged open great breaches in the wall. The Traitors surged into the Palace, killing with renewed fanaticism.

Meanwhile, Jaghatai Khan decided on a change of plan. Rather than assaulting the nigh-invincible bulk of the besiegers' army, Khan redirected his White Scars Legion and the surviving Loyalist Imperial Army Tank Divisions to Lion's Gate Spaceport. The Khan's lightning raid struck at dawn, and surprised the Traitors completely. The spaceport was retaken. Khan ordered his troops to create a perimeter around the port and to reactivate the defence laser batteries. These began firing on Horus' unprotected dropships, as Khan's troops repelled a series of frenzied counter-attacks from the besiegers. Khan's plan had worked: the flow of men and machines to the Palace had been halved at a single stroke. An attempt to re-seize the Eternity Wall Spaceport inspired by this success was in vain.

At the Palace, the retreating defenders had been forced back to the Eternity Gate, the sole point of entry into the Imperial Palace. The Blood Angels and Imperial Fists defied hordes of Chaos troops, while the remaining Imperial Army troops fell back through the Gate. Then the mighty Bloodthirster Ka'bandah came forth, and bellowed out a challenge to Sanguinius. The Angel would never have time to answer. The daemon hurled itself at Sanguinius, barely allowing him time to parry the daemon's strikes. All fell silent. Daemon and Angel took to the sky. Fatigued from the siege, Sanguinius lost the upper hand and was cast down by the daemon, pulverising the concrete below upon impact. The invaders roared with triumph. The defenders wailed in despair.

Yet the Blood Angels' Primarch was not beaten. He had made a promise to the daemon on the Signis Cluster. Now was the time to fulfil it. Sanguinius forced himself back to his feet and took to the sky. Flying as swift as a missile, the Angel took the daemon by surprise. He seized the daemon's ankle and right arm. A burning corona of light playing about his head, now terrible in aspect, Sanguinius hefted the creature high, and broke its back over his knee. Sanguinius hurled the carcass back at the horde which wailed in frustration, as the Eternity Gate slammed shut.

[Icarus Athrasuriel]

Part 6

The siege lasted 55 days. Both sides knew the defeat of the Imperium was near. Sensing this, Horus prepared to teleport to the surface to lead his forces in person. Before this could happen, the Word Bearers First Chaplain Erebus broke the news to Horus: Their daemonic allies had told him that the Ultramarines and Space Wolves Legions were nearing Terra; only a short distance behind them were the Dark Angels Legion. While Erebus knew the other two legions would arrive in mere hours, he could not be precise about the exact time of Jonson's arrival.

At that moment, Horus realised that his gamble had failed. Weeks of further conflict would be needed to break the defenders; the Emperor's reinforcements would arrive in mere hours. It was then that Horus gave the most fateful order of the entire Heresy. He ordered his flagship Vengeful Spirit's shields dropped, immediately. By so doing, Horus hoped to draw the Emperor from the surface and force him into a duel.

The Emperor rose to the challenge, leading his Adeptus Custodes, the Primarch Sanguinius, Rogal Dorn and several Imperial Fist and Blood Angel Space Marines in Terminator armour in the assault. Horus used his powers to scatter the Emperor's force throughout the massive warship. Each fought a series of battles aboard the corrupted ship, attempting to link up with their comrades and confront the Warmaster. It was Sanguinius who reached Horus first. The Warmaster attempted to lure the Blood Angel Primarch to his side; when Sanguinius refused, Horus attacked. Sanguinius, wounded from his battles on Terra, was no match for Horus, now at the height of his daemonic power, power almost enough to rival the Emperor. Horus strangled the Angel with contemptuous ease.

Then the Emperor entered. He saw the corpse of Sanguinius, lying at Horus' feet. Horus told the Emperor he was a fool for refusing the power that the Chaos Gods offered; power that he had used to tame them to his will. If the Emperor would kneel before him, Horus would spare his life. The Emperor knew well the trap that had snared his son. No one could master Chaos, the Emperor replied, Chaos itself was always the master of those it seduced: Horus had deluded himself. Horus was the servant, not the master. Snarling, Horus sent bolts of lightning at the Emperor. The Emperor nullified them. The die was cast: Each god-like being knew the fate of humanity hung in the balance.

The Emperor and Horus engaged one another, battling physically and psychically. Though the Emperor's psychic gifts and martial skills were unmatchable, he found himself unwilling to summon his full power against his first son. He suffered grievous wounds at his fallen son's hands. After a score of thrusts, parries and counter-thrusts, Horus opened the Emperor's jugular and severed the tendons in his right wrist. A psychic blast seared the flesh from the Emperor's face, bursting an eye. Horus tore the Emperor's right arm from its socket, and broke his back over his knee.

At that moment, a lone Adeptus Custodes warrior entered the bridge. Horus showed him the Emperor's broken form and laughed mockingly at the Custode. He roared and charged the Warmaster immediately, only to be incinerated in an instant by a psychic blast from Horus. (In previous editions of the tale, an Imperial Fist Terminator attacked Horus; in older versions, the deed is ascribed to an Imperial Guardsman named Ollanious Pious.)

The casual brutality of the act galvanised the Emperor. Realising at last that his favoured son was truly lost to the corruption of Chaos, the Emperor finally mustered his full power, and unleashed a lance of pure Warp energy that pierced the gloating Horus' defences. So powerful was the attack that the Chaos Gods themselves recoiled in terror, withdrawing rapidly from their mortal pawn. Just before Horus died, he looked his father in the eye, shedding a single tear. The Emperor saw regret in his fallen son's eyes. He also knew Chaos could attempt to possess Horus once more, and that he would not be there to halt him a second time. Driving all compassion from his mind, the Emperor obliterated Horus from the mortal plane.

The Warmaster's death sent a psychic shockwave surging across the Solar System, casting the Chaos daemons back into the Warp, spreading mass panic in seconds. It became clear to the forces of Chaos that their leader had been defeated. A berserker fury encompassed the Blood Angels at the moment of their Primarch's death, and they surged forth to scatter the attackers. Retreat turned to rout, and rout turned to bloodbath; scores upon scores upon scores of Traitor Marines and Titans fell as they attempted to flee.

Meanwhile, Rogal Dorn finally found his way to the ship's bridge, only to discover his fallen brother, Sanguinus, and the Emperor, on the verge of death. It was then that the Emperor whispered instructions to Dorn, urging the Imperial Fists Primarch to take him to the Golden Throne. The surviving Loyalists teleported back to the Imperial Dungeons. Here Malcador the Sigilite, who had briefly taken the Emperor's place on the Throne, thus keeping the warp-gate beyond it closed, collapsed to dust as he was removed and the Emperor put in his place. The Emperor spoke his final words to his followers, urging them to continue the fight to free humanity from the forces of Chaos and ignorance that continued to assail it. And then the master of mankind spoke no more, his body entombed within the life support mechanisms of the Golden Throne, his spirit trapped in a crippled and mortally wounded body for millennia to come. The Imperium of Man survived, but it would become the bastion of repression, superstition and brutality that the Emperor had fought against. It also would offer humanity the only chance for survival in an increasingly hostile universe.

[Icarus Athrasuriel]

The Great Scouring
30,014 A.D. - 30,021 A.D.
014.M31 - 021.M31

The Siege of the Emperor's Palace had ended and Rogal Dorn has completed and enshrined the Emperor's sacred corpse upon the Golden Throne. Remnants of the heretical forces led by Horus are pursued by Ultramarine forces and forced to flee into the Eye of Terror. Several surviving heretic Primarchs are granted their prizes by their respective deity, a planet to shape as they like and base their forces on. The Loyalist survivors scattered across the Imperium begin to reclaim Imperial worlds and several more human cultures are brought into compliance under the guidance of Roboute Guilliman, in addition to the defeat and extermination of many more alien races encountered.

Lion El'Jonson returns to Caliban from the Heresy with his Dark Angels, only to find that his mentor and oldest friend, Luther, has gathered up the Dark Angels on Caliban to his, and the Chaos God's, cause, killing all who oppose him. Luther immediately engages the Lion's fleet, and soon the two are engaged in hand to hand combat. The Lion wounds Luther but cannot bring himself to deliver the killing blow, and Luther lets loose one last sorcerous blast, mortally wounding the Primarch of the 1st Legion. At this point, Luther realises what he is done, and weeps for his friend. The Dark Angels capture Luther, and the his forces scatter, becoming the Fallen. The Lion is put in stasis and placed within the Rock, the Dark Angels new home.

Roboute Guilliman, Primarch of the Ultramarines Legion, compiles the Codex Astartes, a vast tome which details the tactics, organization, markings and rituals of the Adeptus Astartes. The Ultramarines and successors (see below) follow the Index to the letter, as do many other Legions. It is known for Battle Brothers of many Chapters to memorise the passages that pertain to them, so that the entire knowledge of the Codex (or at least that which is useful to the Chapter in question) is held within the Chapter's warriors.

The Second Founding: Upon the decree of Roboute Guilliman, the 8 Space Marine Legions are split into 40 Chapter, with 8 Chapters retaining the name and homeplanet of their source Legion. Many Primarchs and commanders are opposed to this decree, but all eventually accept it as a necessity to avoid another Heresy. Chapters of the Second founding (And the following foundings, defined by order of Chapter creation, not time period) are often referred to as successor chapters.

The Grey Knights Space Marine Chapter are secretly created by the newly founded Inquisition. Their origin is disputed, and they are shrouded in secret.