Xaltotun is an evil wizard from Robert E. Howard's stories about Conan the Barbarian. He appears in The Hour of the Dragon as an ancient resurrected wizard, and serves as the main enemy to Conan. Much of the book revolves around Conan's quest to retrieve the Heart of Ahriman in order to defeat the wizard.
Xaltotun may be by far the most dangerous black wizard Conan ever faces, in any of the Conan stories, although the Khitaian sorcerer Yah Chieng in The Return of Conan, who would have beaten Conan except for divine intervention by Crom, may have been of similar power to Xaltotun.
Conan regularly destroys black wizards through brute force and determined frontal attack - in fact, one of his favourite sayings is "A stout blade is a hearty incantation". Xaltotun is different - the one time Conan faces Xaltotun in direct combat, Xaltotun brushes Conan aside as easily as if he were swatting a fly, blasting him unconscious with a flick of his hand.
The raising of Xaltotun from the dead is the act of inadequate men. Orastes, a frustrated seeker of dark knowledge, wishes for a teacher worthy of his ambition. Valerius, Amalric and Tarascus are second rate nobles who seek greater Earthly power, and hope the harebrained schemes of their "pet" black wizard Orastes might advance their quests. None of them hesitate to consider the wider consequences of their acts.
The consequences of Xaltotun's resurrection go far beyond the conquest of a new empire, or a few lessons in the black arts. Orastes finally understands, and repents too late when he realises what he has done.
"When we employed the Heart of Ahriman to bring a dead man back to life," Orastes said abruptly, "we did not weigh the consequences of tampering in the black dust of the past. We thought only of our ambitions, forgetting what ambitions this man might himself have. And we have loosed a demon upon the Earth, a fiend inexplicable to common humanity. I have plumbed deep in evil, but there is a limit to which I, or any man of my race and age, can go. My ancestors were clean men, without any demoniacal taint; it is only I who have sunk into the pits, and I can sin only to the extent of my personal individuality. But behind Xaltotun lie a thousand centuries of black magic and diabolism, an ancient tradition of evil. He is beyond our conception, not only because he is a wizard himself, but also because he is the son of a race of wizards".
When Conan fights Xaltotun, he is fighting for the future of the world, not just the future of his kingdom. As the following passage shows:
"My Lord, it is ill to say, and I fain would say otherwise. But the freedom of [Conan's kingdom] Aquilonia is at an end. Nay, the freedom of the whole world may be at an end! Age follows age in the history of the world, and now the world enters an age of horror and slavery, as it was, long ago.".
"What do you mean?" demanded the king [Conan] uneasily.
Hadrathus dropped into a chair, and rested his elbows on his thighs, staring at the floor.
"It is not alone the rebellious lords of Aquilonia and the armies of Nemedia who are arrayed against you." answered Hadrathus. "It is sorcery - grisly black magic from the grim youth of the world. An awful shape has risen out of the grim shades of the past, and none can stand before it".
"What do you mean?" Conan repeated.
"I speak of Xaltotun of Acheron, who died three thousand years ago, yet walks the Earth today.".
Orastes explains Xaltotun's ambition to destroy the world as we know it to his fellow plotters.
"And in the last conclave to which I accompanied him [Xaltotun], understanding came to me at last, while the drums beat and the beast worshippers howled with their heads in the dust. I tell you he would restore Acheron with his magic, by the sorcery of a gigantic blood sacrifice such as the world has never seen. He would enslave the world, and with a deluge of blood wash away the present and restore the past.".
In conclusion, the following quote sums up Xaltotun's relationship with the plotters who raised him from the dead - at least, those who are still alive.
Xaltotun turned his inscrutable gaze upon the King. "Conan is wiser than you." he said at last. "He already knows what you Kings have yet to learn - that it is not Tarascus, nor Valerius, no, nor Amalric, but Xaltotun who is the real master of the western nations".
Given such an adversary, Conan understands that mere swords would not do and that to rise up against Xaltotun's power would be to throw away the lives of his loyal subjects. The only weapon which could defeat Xaltotun is the Heart of Ahrimam - and therefore Conan spends the bulk of the book in a quest to recover that jewel and place in the hands of someone qualified to use its magic and destroy Xaltotun.