Just finished game.
My tank warrior (not even lead-main) is immune to everything, have 2.5k HP, never miss a hid and does insane damage both single and aoe. And even more with "resistance nulify" and Rage. Elemental damage does nothing to her, all physical damage drown in shield-blocking.
I have 2 mages (pyromancer and support-jahan), melee rogue and this monster. On last boss melee rogue missed EVERY HIT and damage was ridiculous even with stealth+backstab perk.