Mike Mignola said this quote
“ My Hellboy is modeled on my father in some ways: a guy who's been in the Korean War, and he's traveled, and he's done a lot of stuff, and he's kind of got a been there, done that attitude. He's also been in the world. Del Toro's change was to have Hellboy bottled up in a room and mooning over the girl he can't have. ”