An alien from the planet Nferino who possesses horns, a tail, and cloven hooves. In August, 1970, he manages to successfully charm Lois Lane for a time, in spite of her suspicions that he may in reality be the devil. When Superman investigates the matter, the ensuing confrontation results in a gunshot that accidentally strikes Lois and apparently kills her.
Satdev gives the seemingly deceased Lois a potion that causes her to take on his devilish appearance and then whisks her to his homeworld in order to wed. Superman, believing Lois dead, donates a memorial ring to her estate with a declaration of his affection engraved upon it. Lois is touched by this effort, forgets Satdev, and returns to Earth (SGLL No. 102, Jul 1970: "When You're Dead, You're Dead!"; SGLL No. 103, Aug 1970: "The Devil's Bride!").