Liber Mechanicum: Forces Of The Omnissiah Army Book

The mysterious Cult Mechanicum of the 31st Millennium march to war armed with esoteric and arcane science, hosts of battle-automata and cybernetic soldiers guided by the cold iron logic of their Tech-Priest overlords. The Lords of Mars command the technology that shaped the Imperium and, as the Horus Heresy consumes the galaxy, wield their arsenal for both Loyalist and Traitor causes.