Hykksmoth

 Hykksmoth was the daemon prince of Aksum, an ultroloth who had risen far above the typical position for yugoloths of his type. As a lieutenant of the General of Gehenna he held unspeakable power, and wielded it cruelly.

His lofty position was the result of an eternity of crafty planning, brilliant networking, and the judicious and liberal application of viciousness. He built around himself a many-layered network of underlings, each constantly played off the other both to ensure a lack of competition from below, and for his own amusement.

For many years he served as a battlefield commander in the Blood War, running vast mercenary armies that switched sides at a moment's notice, collecting escalating fees, some of which even made their way into the treasury of the General. After a few centuries of loyal service he requested what many of his peers saw as a dead end assignment overseeing the doomed invasion of the prime material plane.

But where the other yugoloth commanders saw only the opportunity to fail where so many others had failed before, Hykksmoth saw the potential for profit, and the carving out of a tidy kingdom away from the eyes of his peers and his General. He had read about Aksum. He knew the riches to be had there, and he decided to be patient, consolidate power, grow his wealth, and when the opportunity arose and the riches of Aksum began to grow thin – only then would be strike out in conquest, at the head of a yugoloth army funded by the vast treasury built by centuries of hoarding.

The feeble human slaves trapped in Aksum with him were a lucky stroke – he had expected the destroyed city to be empty of intelligent life. The few survivors of the city gave him a cheap workforce and an inexpensive way to buy the loyalty and distraction of his underlings – as long as humans existed in the city the yugoloths under his command would entertain themselves with pointless cruelty rather than ambitious planning.

Likewise, the lich Daern was a lucky find. To have such a knowledgeable slave was rare. Hykksmoth enjoyed the cruelty Daern inflicted on his fellow man, and relished the opportunity to play puppetmaster to the undead wizard.

It was only the unexpected arrival of powerful adventurers from outside the city that finally brought Hykksmoth down. When the Heroes of Anglesey arrived, Hykksmoth didn't learn about them until they attacked him in his stronghold at the top of the Black Tower. He escaped with his life, but at the cost of his control over Daern and the collapse of both the Black Tower and the weather wall that cut the city off from the outside world.

Determined to have his revenge, Hykksmoth rallied his daemon army and gathered them on the edge of the Aksumi crater. There he threw them against the weak human survivors knowing that while Daern's Fleshers might kill many of his daemons, they would eventually break. He sent teleporters and flyers against the refugee slaves, hoping that the heroes who had attacked him in his tower would spend their strength protecting their kinsmen rather than fighting his main force.

Instead, the heroes came to him directly, dropping into his base of operations, slaughtering his bodyguard, and, finally, killing him.