Amnizu

Amnizu, also known as styx devils, were powerful baatezu found mostly on the layer of the Nine Hells called Stygia.

Description
Amnizu were usually around 4 ft (1.2 m) tall and had an elongated, bald head on which lay a mouth full of jagged teeth, a pug-nose, and heavily-browed, large porcine eyes. They had stubby limbs and large leathery wings. If they aged without a promotion, amnizu could grow to up to 10 ft (3.1 m) tall.

Personality
Amnizu were aloof, thanks to their position as members of the 'nobility' of the Nine Hells. They were hateful toward any other baatezu short of a pit fiend or archdevil as they were the creatures in charge of promoting them to an even higher station.

Society
Amnizu were typically charged with one of three duties, either as guardians of the River Styx, as the generals of mighty armies of abishai and erinyes or as the ferriers of new souls into the Nine Hells.