One of the magic-wielding Megans of Megas-Tu, who leads the case against the Enterprise crew when humanity is put on trial in a recreation of Salem.
Asmodeus is a Megan, a native of a universe at the centre of the galaxy where magic takes the place of physical law. He appears in the Animated Series episode The Magicks of Megas-Tu.
Long ago he and other Megans visited Earth and lived among humans, who came to fear them as witches and devils; the survivors fled home after the persecutions at Salem. When the Enterprise is drawn into their realm and befriended by the playful Lucien, the Megans seize the crew and place them in the dock of a seventeenth-century courtroom.
Asmodeus acts as chief accuser, arguing that humans are cruel and will bring ruin to Megas-Tu. Spock speaks for the defence, and Kirk's willingness to risk himself to save Lucien from eternal isolation shows the Megans that humanity has changed.