Tyrant Mechanicus Backstory

This is fluff lore for my kill-team turned primary Tyranid army, the "Tyrant Mechanicus".

Credit to Nikolaus Ingeneri, image from "Deathwatch: The Jericho Reach"

 On a planet far from the dim light of the Imperium of Man, a lesser-ordained splinter cult of the Adeptus Mechanicus toiled deep underground. Far below the surface, in a sprawling manufactorum, the so-called Genetor Extremis discovered the mind-tech used in the manufacture of the revered god-machine Titans could be coerced to affect a mind bi-directionally. 

Blessed with this knowledge, they schemed to use it to control organic matter. The tech priests, in a sacred ceremony to their Omnissiah, implanted a control device into preserved corpses secreted away from distant Tyranid invasion. As Psykers channeled shielding auras into the depths of Blackstone arrays, the censers swung and priests chanted, and the creatures were cleansed and bestowed with the essence of the machine spirit, replacing the Hive Mind of the foul Xenos. These first experiments rose shakily from the metal tables of the morgue, whispering on barbed tongues hardly capable of speech, "Hail the Omnissiah".

This knowledge was shared with only the most trusted Imperial Governors, who naturally wished for a demonstration of the heretical abomination. They bade the Genetor Extremis sic the monsters on various enemies deemed unworthy of the attention of the more proven servants of the Emperor.  More funding and organic material would be forthcoming in the event of success, they promised. They also imparted the threat of heresy in discovery - should the Extremis’ twisted creations be made public knowledge, or should the abominations wrest control back, the Imperial Commanders would claim ignorance and terminate the project immediately with distinct prejudice.

Knowing their existence teetered on the whim of corrupt officials and political theater, the Genetor Extremis relocated to an abandoned death world, a barren planet where the Imperium dare not entreat. There they could perfect their art of resurrection, and hone their implements of war, the extentions of the will of the Omnissiah.

Thus were the legions of the Tyrant Mechanicus created.