Abheilüng is a former Imperial vassal world now controlled by the Dark Mechanicus and wholly dedicated to the Ruinous Powers. It was lost to the Imperium in 995.M41, when elements of the Dark Mechanicus that had long been hidden in the subterranean depths of this volcanic world caused every volcano on the planet to erupt simultaneously, killing millions.
The servants of the Dark Gods then unleashed a horde of Daemon Engines to cleanse the planet of any survivors. Those few unfortunate souls who remained after the slaughter were taken as slaves to toil in the hellish forges of their new, dark masters.
Much of the early history of this isolated world has been lost to the long passage of millennia. Abheilüng was once considered a vital deep void empyreal waystation since it lay on the Armageddon-Paramar Grand Conduit. The survivors of a mission group despatched by the Inquisition to the Abheilüng System recently returned and reported that Abheilüng was now lost to the Imperium.
They revealed that elements of the Dark Mechanicus, who had hidden beneath the surface of the world, employed forbidden rites of techno-pyroclasm to cause the many dormant volcanoes present on Abheilüng to erupt as one, sealing the deaths of millions in a single moment. Worse was to come, for out of the roiling black clouds and rivers of molten rock charged an uncountable host of Daemon Engines.
It was estimated that the entire population of Abheilüng has now fallen to the Dark Mechanicus; slaughtered, consumed or dragged beneath the ground in fetters to tend the infernal forges below. It is believed by many within the Inquisition that Abheilüng is now entirely in the hands of the Dark Mechanicus, which must have lurked unseen in its volcanic labyrinths for centuries.
While that admission galls many within the Imperial government, Abheilüng is now beyond any hope of deliverance. Furthermore, it is likely that Abheilüng is already on the path to becoming a significant locus of production for infernal engines of war and that soon the Traitor Legions and others dedicated to the Ruinous Powers will be able to procure the services of machines wrought in its forges.
- Codex: Chaos Space Marines (6th Edition), pg. 25
- Imperial Armour Volume Thirteen - War Machines of the Lost and the Damned, "The Hell-Forges of the Dark Mechanicus," by Andy Hoare with Alan Bligh and Neil Wylie, pg. 12