A spindly little corrosive weakling with 50% magic res last time I checked.
I agree that the minions are usually the real boss in Vicious. I think the matron makes sense, but The Avatar? He's supposed to be the ultimate apocalypse-wielding demon yet he's weaker than two demonlords. 333 demonlords and a stronger Avatar is what I think should happen.
On the topic of NC: With poison, two kegs, Yendor and Drac as a free above-ground piety farm, it shouldn't be too hard. You can use fire and poison to beat the goo and reflex/quicksilver for Tomithy. The only real problems are Frank and Tormented. Frank is your melee test, Tormentor is your magic test.