Dark Mechanicum - Rise of the Dark Mechanicum: At the outset of the Horus Heresy, the 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 for his dreams of rebellion. Kelbor-Hal was skeptical at first, for the Emperor had been brought to his forge over two centuries earlier, and Kelbor-Hal had been forced to bend the knee to Him.The ruler of the once-lowly Terran techno-barbarian tribes had made empty promises of an equal role in His grand crusade of conquest, but that vaunted equality had never materialised in the fabricator-general's view. The Mechanicum continued to toil in its myriad manufactoria and orbital shipyards across the galaxy's Forge Worlds to provide the Emperor's armies with the needed weapons of war, but received nothing for their efforts but platitudes. Kelbor-Hal knew Horus Lupercal was a warrior of vision, but Kelbor-Hal wanted to know what he could offer in addition to platitudes.Regulus explained to the fabricator-general that much had happened since the Emperor took His leave of the expeditionary fleets after the success of the Ullanor Crusade and the installation of his favorite son Horus as the Warmaster and his proxy in command of the Great Crusade. He assured Kelbor-Hal that alignments had shifted and that new powers emerged from the shadows, offering their aid to those with the strength of vision to heed them. Horus Lupercal was one such individual, and he was now assuredly a friend of the Mechanicum.When it came time to strike at the Emperor and His Imperium, Horus guaranteed to be a friend to Mars as long as the fabricator-general gave his loyalty--and his manufacturing capabilities--over to the cause of the Traitors. Horus also required the fabricator-general to quash any dissent amongst his own Tech-priests so that the forces of the Warmaster would be able to launch their bid for supremacy within the Sol System without fear of counterattack. Any factions loyal to Terra must be brought to heel or destroyed before the Warmaster's forces reached the Sol System.The fabricator-general informed Regulus that the Warmaster had asked much of him and the Mechanicum already. They had already delivered, for they had already ensured that materials and weapons were priority-tasked to those expeditionary fleets of the Great Crusade that the Warmaster favoured and had delayed shipments to those not aligned with him. But the Mechanicum had no desire to trade one autocrat for another.Regulus assured Kelbor-Hal that the Warmaster pledged to return the Martian Empire to its former glory, and furthermore, he swore to withdraw any non-Mechanicum forces from all of the Forge Worlds after the Emperor had been overthrown. To allay the fabricator-general's misgivings, the Warmaster promised to provide the Mechanicum the lost secrets of ancient Standard Template Construct (STC) technology that had been recovered from the worlds of the recently subjugated Auretian Technocracy by the Warmaster's Sons of Horus Legion.The fabricator-general was impressed with the Warmaster's gift, and admitted that it was a valuable STC database, but he wanted more. Regulus had anticipated this demand, and told Kelbor-Hal that the Warmaster promised to lift all restrictions on research into those technologies like Abominable Intelligence (A.I.) that the Emperor had declared forbidden. To cement the alliance between the Mechanicum and the Warmaster and display the Traitors' seriousness about their cause, Horus had provided Regulus with the protocols required to unlock the infamous Vaults of Moravec.The Vaults of Moravec were a repository of forbidden knowledge that the Emperor had ordered sealed two centuries earlier after the signing of the Treaty of Mars, for the vaults contained innumerable artefacts of technology that had been fashioned or corrupted by the malign power of Chaos or were in themselves incredibly dangerous, such as Warp-based weapons and ancient artificial general intelligences like the Men of Iron. Greedily, the fabricator-general struck the dark bargain, accepting Horus' proposal and willingly joined forces with the Warmaster, assisting the Traitors with all of the technology of Mankind at his disposal.