A Lesser Arbitor of Earth  

A Lesser Arbitor of Earth seems to be a substitute for Mystical Arbitor -- he spawns after you complete the 4 ring events in Plane of Earth A, in front of the far zoneline to Earth B (need Gem-Etched Key to get to him). And when you kill him, a planar projection spawns and gives you the flag to Plane of Earth B, "You have been granted access into the chamber of the twelve." and you get "Passkey of the Twelve" on your key ring.