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.
A locked chest, along with one that comes as a reward after slaying the bosses, is on the frozen lake, so a lockpick would be a good idea to have in one's inventory.
This boss is very powerful, doing around 300 damage to casters. Bringing any form of Weakness can be extremely useful, for example by using Enfeeble.