Cohen Lucifer, formerly Cohen Alastor, is one of the current satans of the Underworld, now known as the Seven princes of Hell, and the head of the Royal guard, a special division of high/ultimate-class devils in charge of protect the Grandmaster Devil, the strongest devil with unmatched power. He's the father of Berolina and Nemesis Gremory, as well as husband of Alice Gremory, Grandmaster Millicas' son-in-law and Sirzechs' successor.