Ya that is anoying. I heard an easy way of killing Kack is shooting his mask, then his mask goes flying, you are supposed to see it fly, but I haven't tried it
yea when i first got fable and i had to fight him i went and got all the heath potions i could find in the game(from shops and stuff) cuz i thought i would need them but i only used 3 and the only attck i used was fire ball