Topo the Protector?

Found this boss in Depths of Madness explorable, hes a monk boss where Shiro and the Lich usually are. He kept rezzing Craven Monoliths until I was able to kill him. I've been through here MANY times and NEVER saw him before, and Wiki doesn't mention him. None of my quests have anything about him.

So does anyone have any info, or is he new?

done many runs there, he always spawns, but sometimes he dissappears in the middle of a fight

Hes not new, and only has spell breaker. If you fail to kill him quickly enough he goes away for a while.