User blog comment:B214/Question and Answers 6/@comment-30230931-20190713215117/@comment-37165251-20190713215910

As far as we know there is no single Entity that has the Name Satan.

The Word Satan/Maou/Demonlord is used for the four Original Satans Lucifer, Beelzebub, Leviathan and Asmodeus. Later, when these four died in the Great War and after the Devil Civil War, the Name was used for the Position of Demonlord that are hold by Sirzechs Gremory, Ajuka Astaroth, Serafall Sitri and Falbium Glasja-Labolas.

These four took the surname of the original Satans as her own as a badge of their new position.