Vale of Darkness
Yeenoghu is a Demon Prince, the Demon Lord of Gnolls, and the bestial embodiment of savage butchery. His personal weapon is his dreaded triple flail, created from the bones and skin of a slain god. Yeenoghu commands the obedience of ghouls and ghasts (mainly through his subjugation of the entity known as the King of Ghouls). His worshippers sometimes paint his eye on their weapons and armor so that their patron can see the atrocities they commit in his name.
Yeenoghu combines the worst features of a gnoll and demon in one immense form. Standing 12-foot-tall (3.7 m), his body is gaunt and lanky, and patches of yellow fur stained with brown spots cover him. Leprous gray skin and suppurating wounds mar his body, revealing the corruption of his flesh and spirit. His head is a large, anthropomorphic hyena’s, with glowing red eyes and a toothy maw from which spills strings of drool. He is often depicted wielding a three-headed flail.
As a demon lord, Yeenoghu rules the 422nd layer of the Abyss, aptly and unimaginatively named Yeenoghu’s Realm. It is a salt-swept wasteland bordering a foul ocean in which lurk gnolls, hyena-like creatures, and various carrion-eating undead. Before Yeenoghu took over the layer, it was known as the Savage Searing, ruled by the fallen Celestial demon lord known as Azael. Even before Azael, the layer was realm to the obyrith Lord of Storms and Tempests, Bechard.
Yeenoghu himself lives in a mansion the size of a city pulled by thousands of slaves, which slowly makes its way across the layer.