Inquisitor

Inquisitor Jaq Draco of the Ordo Malleus uncovers hints of a vast conspiracy reaching into the highest echelons of the Imperium, and assembles a strange retinue including a deadly Callidus Assassin and an irreverent squat to pursue the truth. His investigation drags him into heresy, daemonic peril, and secrets that could shatter his faith. As the earliest 40k novel ever published, it is gloriously weird and very much of its era.