Kyuss

Kyuss was an extremely powerful tabaxi who went on to become an obscure deity of the Chultan Peninsula. Known as the the Worm that Walks and Herald of the Age of Worms, he is prophesied to usher in the Age of Worms, a time when the undead will rise and destroy the world.

History
Kyuss was a charismatic prophet in Mezro who led his cult out of that city in -653 DR after persecution from the mainstream followers of Ubtao. Kyuss and his followers founded the religious city of Kuluth-Mar in the Chultengar. His cultists discovered ancient metal plates that foretold the future and confirmed every prophecy that Kyuss had ever made. Kyuss was personally visited by his god, Jergal, who gave him a gift of a single green worm and tutored the man in the ways of necromancy

He began experimenting on the undead, creating such horrors as the Kyuss worm, the spawn of Kyuss and the avolakia. At this time, he gained the services of the red dragon, Dragotha, who he transformed into a dracolich to serve as his general of his undead host. He created a cult around the dogma of life being only temporary, the afterlife a lie and undeath being the one true path to immortality.

While his cultists grew ever more devoted by the apparent truth of his visions, Kyuss tried to fulfill the greatest of his prophecies. He sacrificed powerful magic items and built a massive citadel, the Spire of Long Shadows. At the top of the Spire, he created a monolith through which he channeled the terror, adulation and souls of his entire cult and achieved apotheosis.

However, an alliance of couatls, eladrin wild dwarves and druids trapped him in the monolith, which prevented him from ascending to true godhood and relegated him to a historical footnote.

Two millennia later, a coalition of banites, Bhaalites and Myrkulites known as the Ebon Triad who sought to resurrect their dead gods, initiated a plan to free Kyuss and use his divine spark to achieve their objectives. . In reality, the Triad was created by Kyuss's high priest, the silver dragon vampire Lashonna, who is utterly devoted to him to the point of love, and an avolakia who in its disguised form serves as the Triad's leader.