Wild hunt guy? You mean the werewolf? Cause thats the only enemy I can recall that regens health superfast. You have to play it smart. Use poison sword, thunderbolt potion, igni sign and some bomb and he goes down easy. Each enemy has a very massive weakness, which you need to take advantage of. I had very hard time with those spectrebosses. I gave them no damage at all and I couldnt figure out what I did wrong. Turns out you had to do that trap sign and lure it in there. It loses its spectre form inside it and you can kick the shit out of it easy. If its not a level issue, its the issue of applying the right tactics to the right kind of monster. Which I really like about this game.