What makes this work? The world-weary expression. Amazing details in this piece, but I think I see not a powerful dark person, but someone worn and changed by the (dark? evil?) magics he's used. Congrats on the DD!
Huh... despite the spikes, pointy ears, and red coloration, (as well as the "warlock" title ) this guy just looks world-weary and tired as opposed to devilish. Like the weight of his power rests heavy in that abyssal cloak.