Warlen Mammon, born Warlen Amon, is the 5th Great Satan and former heir of the Amon family. He is Rias Gremory, Sirzechs Lucifer, & Sairaorg Bael's cousin and the uncle of Millicas Gremory. Warlen is regarded as the 4th Super Devil of the Underworld, with Rizevim, Sirzechs, and Ajuka being slightly ahead of him.