Yeenogu, The Eternal Hunger, is a demon lord worshipped by Gnolls. Their symbol is a three-armed flail.
Yeenoghu once rampaged and fed on the material plane before being banished, but during the time that they were unbound they wrought huge destruction and ate all in their path. Legend has it that hyenas followed in Yeenoghu’s wake and fed upon the corpses of those that were slain. Foul demonic magic transformed these hyenas into the first Gnolls.