Oasis of Forest boss DoT extreme damage for level 34

So we were brave took some level 31's into the tower. At the end, fihghting the boss an orc thaumaturgist, who was level 34 i think, he cast a AOE that is kind of overpowering. Howl of the Undying, dealing 300,000 hp damage and 5000 mana drain every tick for like 1.5 minutes. Essentially killing me. However, it does have a recourse of that heals you for 5000 hp. So I stood there and died every tick for 1.5 minutes. The team was able to kill it while I died over and over and had no mana.
While the mob seemed to be attuned to level, his spells are more like raid level spells. How much HP do you think a level 31 has?

PS the loots you can buy at level 31 with the coin is just terrible, its like level 1 gear. One would think it would at least equal defiant gear for the level.