HWWB, I'm not really sold on a non-sentient beast being a character. I mean interesting sure but In my opinion he'd work better as a companion to a sorcerer. Also hellhounds look quite more... hellish. I could see him being some kind of protector spirit or temple dog but again hellhounds don't look cute. It's Hell :P That's if you want to go supernatural though. Or heck maybe there's an otherwise useless character who's only contribution is their awesome pet :P