Thing is, there are plenty of really obscure characters I'm at least 90% sure would stump him - Exelica (from Triggerheart Exelica), the dude from Ikaruga, the guy on the Phalanx cover - but those are no fun.
He got the main character from Shin Megami Tensei: Persona 3. He did not get Satan (from Madou Monogatari/Puyo Puyo). He got Ritsu Sohma (from Fruits Basket) on his second guess (after question thirty).