Man, the fight against the bear was so difficult, he kept killing me. If you don't kill it in the first round, you WILL lose, and I couldn't find anyone teaching how to kill it, so I'll leave my guide here.
First, you'll need a few things.
3 spell's
The kraepelin clones, you get it with the fairies.
Elysian dreams, you will also get it with the fairies.
The smite evil, you get it with willow in day time.
You will need be in your best conditions, full health and mana, Bernadette is pretty much useless, she's weak, but her scream will help you do some damage(even if only 30 DMG lol) bring a bunch of potions and right before fighting it, cure your life and use the clones.
before you Start the fight use the clones, when you start use then to attack and Bernadette, now you will need luck, use the dreams spell and let the bear sleep, in the second round use the clones them pass the round, in the third you will attack with the clones and right after use smite evil. (In my save it died in the third but maybe you will need more, I was level 10.)
What do you think? Do you guys have a better strategy? only this worked for me, and the clones and smite evil are the best to use in the death realm so useful.