Devil

Devils are a lawful evil race of fiends who hail from the Nine Hells of Baator, a dominion of the Astral Sea ruled over by the god Asmodeus. True to their alignment, devils are locked into a strict hierarchy which culminates with the Eight Archdevils, formerly known as the "Lord of the Nine," the powerful rulers of Hell.

Baatezu
This ruling class of devils rule tyrannically over their domains in Baator.

Abishai
Abishai are a subgroup of baatezu created by Tiamat.

Imps
Imps are relatively weak devils typically used as wizards' familiars.