- Real Name: Xaltotun
- Identity: Human
- Occupation: Sorcerer, would-be World Conqueror; former High Priest of Set
- Group Membership: None
- Affiliations: Set, Ahriman, Baal, Chiron, Amalric, Orastes, Tarascus, Valerius, Thugra Khotan, Ptah Mekri, The Old Ones
- Enemies: Conan, Hadrathus, the Priests of Asura, King Nimed, the people of Aquilonia/Nemedia, Hyborian Barbarians, Thoth-Amon, Priests of Stygia
- Known Relatives: Xaltana (The Witch Queen of Acheron, sister)
- Aliases: None
- Base of Operations: Currently unknown; formerly Python, Acheron, Khemi, Nemedia
- Powers/Abilities: Xaltotun was a sorcerer of great knowledge and power. In the time of Acheron, he was perhaps the most powerful mystic on the planet. His powers were vastly amplified when he used the Heart of Ahriman, which enabled him to cause sudden floods, avalanches, deadly plagues, and other forces of mass death and destruction. He could cast illusions, generate consciousness-robbing mists, paralyze others on contact, and animate inanimate objects. His own abilites however, could be overcome by another mystic in possession of the Heart of Ahriman. Xaltotun also held other magic items, such as the Heart of Tammuz, the Hand of Nergal, and a Sleep Crystal.
- Weaknesses: One of Xaltotun's weaknesses is the Black Lotus; a narcotic drug which robs him of his senses when he enjoyed its effects.
Xaltotun held the Heart of Ahriman, never invoking it, but instead guarding it, lest it be used against him.
A few days after the death of his sister, Xaltana, he was engaged in a ritual, involving the blood sacrifice of three virgin youths and the sevenfold symbol. Red Sonja, having been sent back to Acheron (along with Conan) by the mirrors of Tuzun Thune, arrived in a pit below Xaltotun's altar and climbed to the surface in time to see him preparing for one of the sacrifices. Red Sonja failed to stop the slaying of the young woman, but did manage to knock the Heart of Ahriman from his grasp and escape back down into the pit. Xaltotun tried to locate her using the Heart of Tammuz, but the Heart of Ahriman's magic shielded her from detection. He then sent one of his demon familiars after Sonja. It succeeded in catching up with her and had overpowered Sonja, before she managed to tap into the power of the Heart of Ahriman and destroy it.
As Sonja fled to the outside of the city, she ran smack into a gathering of various Hyborian tribes, who had assembled to overthrow Acheron. A shaman decked out in a feathered costume recognized the Heart of Ahriman and snatched it from her grasp. Sonja, exhausted from her struggle, chose not to fight for the gem, but rather returned to the city, to relocate Conan. Meanwhile, Conan had stirred up a rivalry between the Acheronian Guards and a few Cimmerian guards, which served only to help the Hyborian army to burst through the gates of Acheron and storm the city. The feathered Shaman, using the Heart, managed to overpower Xaltotun's sorcery.
Around 10,000 BC., Xaltotun's sarcophagus was located and brought to Belverus, the capital of Nemedia, by four would-be rulers: Amalric, Orastes, Tarascus, and Valerius. Orastes, a former priest of Mitra, had obtained the legendary Heart of Ahriman, with which he called upon the Old Ones for the power necessary in reviving Xaltotun. The mummy burst forth from the sarcophagus, slowing regaining its original form and much of its memories.
The four conspirators explained their plot to Xaltotun—to take over the throne of Nemedia and then conquer Aquilonia, and from there to overtake the whole civilized world. Their greatest obstacle would be Conan, the king of Aquilonia—a descendent of the Hyborians who had defeated Xaltotun years ago.
Xaltotun used the Heart to conjure a great plague, which struck down many in Nemedia, including King Nimed himself. As planned, Nimed's younger brother, Tarascus, assumed the crown of Nemedia. Tarascus called for the overthrow of the "god-defying usurper" Conan from their sister kingdom, and his replacement with Valerius, the rightful heir. King Tarascus' good friend, Amalric, supplied the money to armor the many legions of Nemedia and set them against the forces of Aquilonia. In a valley near the Valkia river, the two forces met and prepared for combat. The night before the battle, Xaltotun ambushed King Conan and afflicted him with paralysis. Not wanting his troops to despair without the fighting spirit of Conan, he had a look-alike, Valannus, outfitted with his battle armor and helmet, and pretend to be him. The ruse worked; the men believed Valannus to be their ruler and followed him into Xaltotun's trap. This resulted in the death of Valannus (which was believed to be the death of Conan) as well as five hundred of Aquilonia's finest warriors, as Xaltotun brought the peaks of the mountains above Valkia crumbling down on top of them.
At this news, Conan forced himself to overcome his paralysis and attacked Tarascus and his soldiers. Xaltotun generated some mists that robbed the Cimmerian of consciousness, but refused to allow Tarascus or any others to finish off the King. Instead, Xaltotun planned to slay him later during a ritual ceremony.
Xaltotun demanded that the news of Conan's survival be kept secret, even going so far as to slay some of Tarascus' soldiers to prevent them from revealing what they had seen. The wizard then brought Conan to Belverus, where he offered to return Conan to his throne in exchange for total obedience. Conan, of course, refused, and Xaltotun taunted him with images of his troops fleeing from the Nemedians, with defeat imminent. Conan rushed the wizard, but was stopped by his servants and then the senses-robbing mists of the Heart of Ahriman. Conan was imprisoned in the crypts below the city, but escaped with the aid of Zenobia, a woman who he had never met before, but who had loved him from afar and wished him to survive and defeat the evil of Xaltotun. Meanwhile, Tarascus, fearing Xaltotun's power and not trusting his intent, stole the Heart of Ahriman from him while he slept after smelling a Black Lotus. Tarascus gave the Heart to one of his soldiers, instructing him to cast it into the sea. Tarascus informed Orastes that Conan yet lived and requested his aid in slaying the former monarch before he escaped altogether.
Without a King, the Aquilonians welcomed the reign of Valerius, rather than begin ruled by Count Trocero of Poitain, who was left in charge by Conan himself. Meanwhile, based on the advice of the witch Zelata--"Find your Heart"--Conan returned to Tarantia. There, he rescued a countess, Albiona, from execution. Fleeing, they ran into the Priests of Asura, who helped them escape. From the priests, he learned that the Heart, of which Zelata had referred to, was the Heart of Ahriman. Conan set out to find the Heart of Ahriman.
Conan infiltrated the Temple of Set in Khemi, where, after much struggle, he claimed the Heart of Ahriman and headed back towards Aquilonia, where he gathered his forces to confront those of Xaltotun and the conspirators. Conan gave the Heart to Hadrathus, the Priest of Asura who had helped him before. At the same time, the conspirators plotted against Xaltotun, correctly fearing that he planned to enact an immense blood sacrifice in order to restore the empire of Acheron. Xaltotun confronted the group and slew Orastes, knowing he was the only potential threat to his existence. The sorcerer revealed to the remaining three that Conan was still alive, but proclaimed that the power of the Heart made him unconquerable. Xaltotun obviously hadn't realized that the Heart had been stolen by Tarascus, and Tarascus did not volunteer the information, hoping that the wizard still had sufficient power to defeat Conan and his forces, but would then be vulnerable to him, Amalric, and Valerius.
Xaltotun led the assault against Conan's forces, planning to lead them into a sudden flood. However, the heavy rains summoned by Xaltotun failed to have their full potency, and Conan's forces continued their advance. Valerius and his forces fell prey to a trap of thousands of Aquilonians, cloaked by a dense fog generated by Hadrathus, using the Heart of Ahriman. Xaltotun prepared a virgin sacrifice to Set and his other dark gods, but was interrupted by Hadrathus, who revealed that he possessed the Heart. Enraged, Xaltotun rushed Hadrathus--and was impaled on the sharp sword of Conan, who had accompanied the Priest of Asura. Xaltotun collapsed to the ground and, in death, returned to his previous, decayed form. Conan placed the body of Xaltotun on his former chariot and sent its horses rushing into the battle where the Nemedians were falling before the Aquilonians. Conan himself slew Amalric and defeated Tarascus, forcing him to surrender.