Pit Fiends

Taken from Monster Manual Edition 4)

Nobles of the Nine Hells, Pit Fiends make an elite governing class that rules vast numbers of lesser devils. Only Archdevils have more power than them. They also serve as vassals to the Archdevils. Each Pit Fiend is lord of a large domain within one of the layers of the Nine Hells. In fact, they are so high in power next to the Archdevils, that if one was to destroy the defenses of its own castle, the castle itself, and the pit fiend, that one person would gain true honor and respect.