Malevo the Living Ghost, First Lieutenant of Satan appeared in Adventures into the Unknown #1.
Malevo the Living GhostArmor: 16, HD: 10 (66 HP), Movement 120'/120' (Fly), 1 slam (2d6 damage Morale 12
Because of God's curse, Malevo can never truly be killed, only temporarily driven away. Normally he can only be harmed by magic (and magic weapons), though certain relics render him temporarily vulnerable to mortal hands. In addition, one per day he can cast Animate Dead Monster as a 10th level Magic-User.