Does anybody know where to find the demon and the dungeon and where to find Sarevok after that? I also need to find out the second part of the riddle in what's his name's dungeon? I think I goes something like this: "find the path that leads away and you will find the path that leads to. ??? Thank you.

I think you mean the demon you fight after doing Durlag's Tower, right? ("Debbie Does Durlag's?" ....nah.) He's waiting for you back in Ulgot's Beard. As for your second question, "the second part of the riddle in what's his name's dungeon," I think you may be referring to some small fragment of the sprawling monstrosity that is Durlag's Tower. I appreciate your being careful about spoilers, but I have nowhere near enough information to help you. Try again, we'll be here.