This is a problem that came with 5.0. I really don't know the mechanic of this boss - they will randomly target and unleash massive damage on someone. Coming at lvl 11 or 12 makes it much, much easier however, since you can survive the barrage.
Colin Quinn Recipe for success/dinner. 1/2 cup of brass you know whats, a tablespoon of I don't give a care, and a pound of get off my back, jack!