The Assassins of the four major temples of the Officio Assassinorum -- an Eversor Assassin, a Culexus Assassin, a Callidus Assassin and a Vindicare Assassin. Unlike other warriors of the Imperium, who are able to focus on war and war alone, the Assassin must be truly autonomous.

a-copyNpaste-from-this-google-search: the three imperial warhammer 40k assassins