Xaltotun is the main villain of the Conan the Barbarian story "The Hour of the Dargon" by Robert E. Howard and its comic book adaptations by Marvel and Dark Horse.
He was the ruler of Acheron, an ancient dark empire of wizards who worshipped the snake god Set.
In the story he's ressurected by a Group of conspirators who wanted a powerful ally to help them overthrow Conan, the king of Aquilonia. These conspirators were Orastes, Tarascus, Amalric and Valerius.
However, Xaltotun cared very little for their ambitions and he plans to recreate the empire of Acheron with a massive blood sacrifice.
He's eventually defeated by Conan and his companions by using an artifact called the Heart of Ahriman.
- Xaltotun is probably the most powerful evil wizard ever encountered by Conan. The one time Conan tried to fight Xaltotun with brute force, he quickly brushes the Cimmerian aside and paralyses him.
- Xaltotun is similar to Akivasha in the movie Kull the Conqueror: Both are ancient and mummified evil sorcerers who are resurrected by conspirators in order to overthrow the hero.