Mary Beelzebub(メアリー・ベルゼブブ; Mearī beruzebubu), previously known as Mary Purson(メアリー・プソン; Mearī Puson) is one of the current Seven Great Demon lords, the wife of Calico Belphegor and Irene Dantalion's mother. She's also Alice Gremory's best friend and Cohen Lucifer's rival in the Highschool DxD: Яe-birth. She's one of few surviving devils that fought during the Great Apocalypse, making her a living legend and a hero among her peers. Mary is the Chief Advisor for the Technology Department, Succeeding Ajuka Beelzebub, being also a doctor at the Beelzebub hospital