Fabricator-General - Schism of Mars: Though the Mechanicum now served the Imperium, there were many amongst their number who were full of discontent at the new order. The Emperor had imposed an exigence of His own upon the Mechanicum.Well aware of the sad story of the Men of Iron and the inherent danger and vulnerability of certain technologies to the corrupting influence of Chaos, He forbade the Mechanicum to pursue certain types of knowledge, foremost amongst those the development or study of Silica Animus; machines that possessed full self-awareness and were totally independent of Human control.The Emperor listed a number of machines and technological concepts that could lead to the combination of technology with the sorcery of Chaos, and ordered those subjects to be considered taboo, and not to be researched by the Tech-priests under pain of execution.Since many such forbidden technologies already existed in various magi's forge cities or lay hidden beneath the sands of Mars, the Emperor ordered the Fabricator-General Kelbor-Hal to seal all such devices within a special cache that only He or His trusted representatives could open, known as the Vaults of Moravec.The Mechanicum grudgingly acquiesced to this arrangement, but the restraint on the Tech-priests' search for knowledge, even dangerous knowledge, would create resentments that would later reemerge during the Horus Heresy over 200 standard years later.At the outset of the Horus Heresy in 005.M31, the Chaos-corrupted Warmaster Horus sent Regulus, a Mechanicum representative who had already thrown in his lot with the Warmaster, to Mars to secure the tentative support of the fabricator-general of the Mechanicum, Kelbor-Hal. Kelbor-Hal was once a brilliant magos of the Mechanicum and a deep believer in the doctrines of the Machine God.The fact that such an ambitious and duplicitous individual ever rose to prominence and the eventual leadership of the Mechanicum is one of the great tragedies of Imperial history. It is remarkable to Imperial scholars of today that an individual as extraordinarily gifted as Kelbor-Hal could be so wrong-headed as to bring so mighty and august a body as the Mechanicum over to the service of heresy and rebellion.When the Emperor had first come to the Red Planet, the masses of Mars believed that the Emperor was the Omnissiah, the physical avatar of the Machine God, a golden figure that trod their planet's red surface. But to Kelbor-Hal and those of his ilk, they believed the Emperor to be a false god who had enslaved the Martian priesthood to His will with lies.This bitter resentment, harboured over the next two Terran centuries, would fester below the surface, until such time when this rancorous hatred would boil over into a terrible rebellion against the authority of this false god. Playing upon the fabricator-general's resentment, greed and bitterness, Regulus convinced Kelbor-Hal of Horus' resolve to support increased autonomy for the Mechanicum against the autocratic rule of the Emperor.As a show of his appreciation for the fabricator-general's support, Horus provided information to the fabricator-general that would allow the tech-priests to open the Vaults of Moravec, the repository of forbidden knowledge sealed by order of the Emperor nearly two standard centuries earlier.When this repository was reopened, there was all manner of forbidden arcane knowledge and weaponry that had obviously been tainted by the corrupting influence of Chaos stored within. Soon the corruption spread throughout the forge cities and temples to the Machine God across the Red Planet as scrap code -- Chaos-contaminated digital source code that was infected with an arcane computer virus -- infested the logi-stacks and cogitator (computer) archives of the Mechanicum, causing literal Chaos to emerge in any cogitator system that was networked to one of its infected counterparts.Soon the various factions fought one another in open warfare, known as the Schism of Mars, as each side declared themselves for the Traitors' or Loyalists' cause. Following seven Terran years of civil war and untold bloodshed, the Horus Heresy ended in a pyrrhic victory for the Imperium.The traitorous forces of Chaos that had served Horus were driven towards the Eye of Terror during the brutal military campaigns remembered as the Great Scouring. The Renegade tech-priests of the Dark Mechanicum were also driven from Mars by the resurgent Loyalists amongst the Mechanicum, who had renamed the organisation the Adeptus Mechanicus to cleave it from the corrupted body of the old Martian government.These Renegades fled the Imperium into the far corners of the galaxy and some also took refuge within the hellish realms of the Eye.In exile, the Dark Mechanicum became even more enthralled to the power of the Warp and heretical technologies. The ultimate fate of the traitorous Fabricator-General Kelbor-Hal is currently unknown.