Zestial is a demon and one of the many powerful Overlords of Hell, as well as the oldest Overlord.

Zestial speaks in an archaic dialect redolent of Early Modern English similar to William Shakespeare. He has a very sophisticated way of speaking and often keeps his temper rather than getting easily frustrated. His reputation is such that demons other than his fellow Overlords are terrified of him, hiding or cowering whenever he passes by. Befitting his advanced age, Zestial is extremely patient and cautious.