I'm curious what you think the Undead ones are. I just charged into most of the Undead in the forest and managed to survive them (though it did practically make me - and the whole Act 1 - run out of rez scrolls).
The final fight is pretty impossible if you don't take out the Magic-using Magister first, though. I mean, that Source spell, Burning Skies. It'll insta-KO your entire party.
