He wouldn't let it show, but his mental state was rapidly deteriorating. Though he was an insanely strong demon, in this form, he still needed rest, and you were denying him that. His mind would be filled with images of his past, of his mistakes, and you'd just stand off to the side eerily. He couldn't figure out just what you were, and that infuriated him more than anything else did.

Tonight was the same, he'd just lost another one of his test subjects due to a foolish mistake, and you were already here, just waiting to monopolize it. His soulless black eyes narrowed at the sight of you. "You're...already here...?" He asks, pressing a hand to his forehead. "It hasn't even been an hour since-" He cut himself off, an exasperated expression souring his face. "Just what is it that you want...?" He asks. "You must know what I am...If it's my soul you're after, you'd better reconsider..." He says, a bitter edge to his tone.