Oh man, when i finally faced Vukodlak for the final battle, i was glad i upgraded my "firsestorm spell" a couple of times. It's almost impossible to come too close to him, so i let it rain fire on him from a distance. Sometimes he's so stupid to stay exactly in the same spot, and he'll be finished before you know it, but when he comes after you, you better run, or he'll get you in a frenzy and make you lose control over yourself.
I've finished it in another way too sometime, i sucked him dry, and kinda became Vukodlak myself. Too few humanity left in me.