Moloch
Moloch is the Pit Baron boss found in the realms of Stonehenge. He is eternal, so repeatable slaying of this Demon is possible.
A great and powerful Demon known as Moloch resides in the rough countryside surrounding Stonehenge, and only the worthy may enter his domain. Characters that have collected the Heads of the Beast, Necro, Spectral, and Primus overlords can then make their way deep into the realms of Moloch, the Pit Baron.
Moloch has very unique items that can only be won by defeating him in combat, so the journey to his defeat can be well worth the effort. His soul is eternal, however, so the process of opening his sanctum and destroying his corporeal form is a never-ending challenge.
(description taken from the Stonehenge Chronicles update notes)