Xerxes is the familiar of the sorcerer, Mozenrath. He is a floating eel/lamprey-like creature, who speaks in broken English.
Xerxies is endlessly loyal to his master, though he has the habit of saying the wrong thing and taking a beating for it. And yet despite the abuse, he gets from Mozenrath, Xerxes remains faithful to his boss. He can also be even as sadistic as Mozenrath.