I love the master librarian, and I love that he looks like he has serious issues. Very consistent with 40K's 'the warp is dangerously seductive' ethos. He looks like he's hearing whisperings but his heart's not turned (yet). Every bit the badass you expect a master librarian to be. When this guy falls he will take many with him. See this is why you should cap the psykers, Templar style.