What kind of creatures are in hell?

I'm writing a book about two guys who have the same near death experience and go to hell, they've encountered a lot of crazy sh'it already but I'm thinking of adding some biblical hell dwellers, also if you could tell me in more detail how they're tortured or who tortures them, that'd be great. Oh and, anything to add that's in donte's inferno? Also, nothing about satan, in my book there is no satan, hell is kind of alive and tortures you itself.