Ultane is the last boss in Grim Awakening.
Really fun fight if you ask me.
I enjoy the hectic part at the end. Dodging 6 waves without stepping out of the circles while trying to keep people alive is interesting !
His loot doesn’t seem very impressive, T2 relic pants if lucky and some half broken upgradable trinkets. So if you’re doing it for the loot you won’t get such big rewards. But if you’re there for the fight itself, you’ll be rewarded with the “Oh yeah !!!!” feeling when this boss goes down.
Good luck !