Yeenoghu

The Demon Prince of Gnolls leads his forces to war.

Yeenoghu shows some Abyssal Ghouls their place.

Yeenoghu is one of the Demon Princes of the Tanar'ri in Dungeons & Dragons. Hailing all the way back to 1st edition, he is one of the original Demon Princes created by none other than Gary Gygax. His fortunes have risen and fallen over the editions, starting as a powerhouse in 1st and late 2nd edition, fading away in significance in 3rd, and experiencing a restoration in 4th.

Yeenoghu's traditional title is as the Demon Prince of Gnolls; he is their master and patron god, although in most editions he only acquired the title by kicking the shit out of their original god, the minor Giant deity Gorellik, and claiming them for himself. This position was strengthened in 5e, when he accidentally created the gnolls - hyenas flock to him, and when they eat his kills, they transform into gnolls, and he's just accepted that this shit happens - instead of pinching them off of someone else. He used to be the patron god of Ghouls in the first two editions as well, having subjugated their Demon Prince, Doresain, but he lost control over Doresain in 3rd edition and hasn't recaptured him since.

Yeenoghu's other title is as the Demon Beast of Butchery. Since demons in general are pretty kill-happy, you can get a rough guess of just what kind of slaughter-crazed lunatic that Yeenoghu is in order to stand out for it. However, he's as much Slaanesh as he is Khorne; he relishes torture, mutilation and agonizing death as he does war and slaughter. In fact, it's the best fun to leave enemies dying in hideous pain from shattered skulls, rent bellies or shredded limbs; killing them quick is boring. When not leading one of his endless battles or partaking in torturous sacrifices, he likes to relax in his massive harem, a motley array of races and creatures whose members constantly fluctuate as Yeenoghu acquires new ones and loses old ones; those who don't commit suicide, die of some disease or get murdered by their fellows to stay alive tend to get either raped to death, killed for the hell of it, or end up being eaten when Yeenoghu grows bored or hungry.

His traditional domain is never named, beyond being called "Yeenoghu's Realm". In his 4e Demonomicon entry, it's described as a foul and corrupt wasteland. A blood red sun hangs low in a sickly green sky, illuminating the whole mess, which can be divided into five distinct regions; the Dun Savannah (endless parched savannah with the odd brackish pond, stand of gnarled trees or mobile and hungry killer plant for variety) of the center, the Screaming Peaks (ghoul-infested jaggedly sharp mountains) of the north, a nameless region of salt flats beyond the Screaming Peaks, the poisoned yellow sea of the Cursewallow to the east, and the diseased, toxic creature-infested Seeping Woods of the west. Yeenoghu rules from a filthy city mounted on giant stone wheels, which armies of slaves - demons and mortals alike - labor to drag in an endless patrol around the Dun Savannah, allowing Yeenoghu to complete a circuit of his domain every year.

Yeenoghu has few allies, which in 4e is because of his tendency - alarming even amongst his own kind - to betray (and usually eat) those who are foolish enough to pact with him. His traditionally greatest rivalry has been with Baphomet.