Dark Mechanicum - Beyond the Imperium: The Adeptus Mechanicus hold their darkest hatred for those Renegade forces of their own brethren that turned on them during the Horus Heresy, Traitors who live on to this day as the Dark Mechanicum. The forbidden histories of those terrible days show that the destruction wrought by the Traitors on Mars and in a dozen other spheres of war was unparalleled, and has left a stain on the soul of the Omnissiah's priesthood that has never been cleansed.In the aftermath of Horus' fall, many of the Dark Mechanicum who survived found sanctuary with the various Traitor Legions and in dark corners of the Imperium where their terrible arts have prospered and their undying hatred of the Imperium has festered down through the millennia.The forbidden psycho-sonic weapons of the Emperor's Children, the gene-atrocities of the hated Fabius Bile, the malign perversion of the techno-viral technology used to create the terrible Obliterators -- all have been laid at the Dark Mechanicum's door. Hellish Forge Worlds bestrode by cyber-daemonic overlords deep within the Eye of Terror ceaselessly churn out the weapons and munitions that arm the forces of Chaos and fuel the dreaded Black Crusades.The Renegades of the Dark Mechanicum were amongst the first group of those the Imperium branded as "Heretics," and they willingly fled to the Eye of Terror where they could live forever beyond the Imperium's control. But the Eye of Terror was not the only region of space where these Heretics fled to escape the Imperium's wrath.Though the Imperium is vast, its authority stretching from rim to rim of the galaxy, in reality there are vast swaths of space that remain hidden from the Emperor's light. These regions have many names, including but by no means restricted to, the "outlands," "wilderness space," and the "Halo Stars." Within them, whole civilisations can rise, prosper, and fall, without once knowing of the wider Imperium that surrounds them.The Calixis Sector is one such region of space, lying along the edges of the galaxy, an established bastion of Imperial control amongst the hazy borders. However, it is surrounded by regions of space not under Imperial control. The most prominent is the Koronus Expanse in the Halo Stars, linked to the Calixis Sector by a fluctuating Warp passage.Beyond this passage, Imperial rule ends, and all manner of Human and xenos civilisations exist unknown and undiscovered. However, there are other outlands around the Calixis Sector as well, including the Hazeroth Abyss, the fringes of the Drusus Marches, and the nomad space between the Calixis Sector and the bordering Ixaniad Sector. The Renegades of the Dark Mechanicum tend to be as varied as the regions of space they occupy.Frequently, Hereteks take the form of extended clans that share their knowledge only through their blood relatives, maintaining a level of understanding about ancient technologies or local Warpspace conditions that astounds outsiders.The Adeptus Mechanicus is particularly sensitive to the existence of such Hereteks (of which those in the Meritech Clans are a particularly egregious example) and press other Imperial authorities to mobilise and capture or kill them as a matter of priority. Individual Renegades sometimes slip into Imperial space to pursue their trade, but they find it a dangerous place to live. If caught and identified, they are tortured and executed by the Inquisition with no hope of mercy.