Warhammer 40k's Eisenhorn: The Omnibus collects Dan Abnett's original trilogy—Xenos, Malleus, and Hereticus—following Inquisitor Gregor Eisenhorn's journey as he delves into grim conspiracies, confronting heresy, aliens, and daemons on the fringes of Imperial law, eventually leading to darker paths and encounters with other notable characters like Ravenor, offering a deep dive into the universe's darker corners through noir-infused sci-fi.