Eldritch Ettin is a warrior boss found at the end of the 3rd level of the Bloodstone Caves. He has his own entourage of 2 First Inscribed boss-like foes.
Each of the three are flocked with Enchanted Shields and Enchanted Scythes.
This makes the group difficult to take down, and often takes a long time to do so. Thankfully a respawn point is within a 20 second running distance from the bloodstone that they all inhabit.