I could be completely mistaken, but from our understanding, he seems to hit for a sort of "true magic" damage (for lack of a better way to describe it) He actually hits dps for the same amount as he hits a tank with his attacks, ontop of that, shields and avoidance dont work anyway, so the only reason to have a tank on him is threat and shear HP. Mercenaries (i realise they cant taunt) actually take the least damage i believe, cus they have most damage reduction from talents. So aslong as the dps can taunt, it should be ok. And as said previously, assasins(shadows) can even take an enraged pylon landing on their head purely with their 5 sec magic immunity, so if u have 2 of them, you can go on forever