Supreme One, Satannish the Supreme, Master of Souls, Mister Cloot, Satan, numerous others
Unknown to most of humanity
Hell dimension ruler
Place of Birth
Unknown, possibly Dark Dimension
Doctor Strange #174 (1968)
Heroic sorcerer Doctor Strange has sometimes invoked Satannish's power, but has never entered the demon's service; he first encountered Satannish when minor mystic Lord Nekron tried unsuccessfully to sacrifice Strange's soul to Satannish in place of his own. Shortly thereafter, a faction of the Sons of Satannish cult led by Asmodeus (secretly Strange's old medical colleague, Dr. Charles Benton) tapped Satannish's power in a world-threatening scheme thwarted by Doctor Strange, the Black Knight and the Avengers. Dying of a heart attack in battle with Strange, a resurrected Asmodeus later tried to win back his life and soul by seeking the souls of the Defenders, but he was defeated and Satannish claimed him. Satannish's subsequent schemes have been opposed by champions such as Strange, Daimon Hellstrom, Luke Cage, the Hulk, the Avengers (who twice fought the Satannish-empowered Hangman) and Hellcat.
Though he once teamed with fellow Hell-Lords Mephisto and Thog to create a temporary Hell on Earth with the unwitting aid of the Six-Fingered Hand (a scheme thwarted by the Defenders), Satannish has long pursued a bitter rivalry with Mephisto, notably during their battles over the souls of Baron Mordo (a fight broken up by Strange) and Satannish's Lethal Legion (the souls of evil historical figures which were stolen from Mephisto and pitted against the Avengers). Satannish ultimately tried to conquer all Hell realms on behalf of his mentor Dormammu, but their coup failed and Mephisto seemingly destroyed Satannish. Since Satannish's demise, a virtually identical demon known as Molgotha has appeared, but how or if he is related to Satannish remains to be seen.