Ahzek Ahriman has the unique distinction of being both the first and last Chief Librarian of the Thousand Sons, and is the most gifted mystic among their already-formidable psyker corps. A respected commander even before his Legion's reunion with its missing Primarch, Ahriman's keen intelligence and talent in warpcraft soon made him Magnus' foremost apprentice, but his greatest strength is his indefatigable will. Ultimately, this determination would see him play a pivotal role in the Burning of Prospero – and walk strange and terrible paths long after the close of the Horus Heresy.