Urthona was created by writer Peter Gillis and artist Chris Warner, and while he first appeared in Doctor Strange #79, the Sorcerer Supreme of Earth senses the alien conqueror's presence in the preceding issue.
Urthona hails from a distant planet named Gevaltu, in an unknown galaxy far, far away. His penchant for magic created a desire to become the Sorcerer Supreme over the entire universe. Because of this, he wished to kill the Sorcerer Supreme of Earth, Doctor Strange. To this end, he sent his warrior champion to Earth to slay Strange. Urthona's warrior managed to wound Strange, but the sorcerer's astral form possessed Morganna Blessing. Through her, Strange used black magic to summon the demon Satannish to consume the champion. While Strange struggled to return to his body, Urthona sent his warriors to Strange's sanctum sanctorum, where they captured the Sorcerer Supreme's manservant, Wong, and his ally, Topaz. At some point in the past, Urthona had somehow obtained a piece of Topaz's soul from Mephisto's realm. The alien sorcerer used the fragment to torment Topaz, while also torturing Wong. Doctor Strange went directly to Gevaltu with the loan of a Skrull spaceship from the Fantastic Four and the aid of Rintrah, who acted as the host for Strange's astral form. In the end, Strange defeated Urthona by freeing Topaz' soul fragment and destroying the Darkhold and the other tomes and talismans Urthona had claimed as spoils from the stolen sanctum sanctorum. It was the destruction of the Darkhold herein that later allowed vampires to be reborn in the Marvel Universe.
Though Urthona was exiled from Gevaltu, he later returned to his homeworld. The destruction of Pura-Shamutra led Strange to the planet and another encounter with Urthona. Strange defeated Urthona and exiled him to an unidentified realm to consider his misguided ways. Pura-Shamutra was subsequently resurrected by Strange.
Urthona may have been among the extra-dimensional forces freed in the United Kingdom by the Skrulls during the Secret Invasion, but the Sorcerer Supreme of Gevaltu has yet to further pursue his feud with Stephen Strange.