Seven Great Satans

The Seven Great Satans (七大魔王, Nanadai Maō) were the original rulers of Hell and leaders of the Devils, Succubi, Incubi and Imps. They were named Lucifer, Beelzebub, Leviathan, Asmodeus, Belphegor, Mammon, and Satan.

Summary
At some point in the past, the seven original Satans led the Devils against God and the Seraphs in Heaven, the original Vampyre and his Vampyres and Dhampyrs, the Original Hero and his Heroes, as well as Azazel and the Fallen Angels in the Great War, the latter of whom retreated prior. The Seven Great Satans eventually died in the Great War after more than half of the 72 Daemons as well as a majority of the armies of Devils, Succubi and Imps that serve the High-Class Devil Clans of the 72 Daemons were wiped out.

After their deaths in the Great War, a group of the descendants of the Seven Great Satans intended to carry on their legacy by gathering the strong supporters of the original Seven Great Satans and finish what they started, the Great Mythology War to realize the world domination ambition of the Original Satans. Their intention however, were opposed by a certain group of Devils, the Anti-Satan Faction, who wanted to ensure the survival of the Demons as a species, thus disapproving of the continuation of the Great War. This dissension eventually caused a civil war to break out between the Devils which ultimately lead to the defeat of the Original Satans' descendants. Following the defeat of the descendants who were forced to retreat to the back part of Hell, their names became titles for the new rulers of the Devils while the Original Satans became known as the Old Satans.

The current Satans are Percival Lucifer (a direct descendent of the Original Lucifer), Serafall Leviathan (of the Sitri Clan), Myrddin Beelzebub (of the Astaroth clan), Kason Belphegor (of the Gremory clan), Bonnibel Belial (of the Belial clan), Harribel Mammon (of the Zepar clan), and Fallnir Asmodeus (of the Glasya-Labolas clan), seven Devils who were born with immense power, equivalent or superior to the original Seven and were chosen for the Satans' positions, despite six of them not carrying the blood of the original Satans.

Five of the descendants of the original Satans – Tsufaame Leviathan, Zakhen Mammon, Zolgear Belphegor, Olba Beelzebub, and Creuserey Asmodeus – have allied with the Chaos Insurgency's Old Maou Faction, while Percival Lucifer, Railane Lucius Lucifer and Dredge Leviathan joined the Anti-Satan Faction. The three last known remaining descendants of the Seven Great Satans, Drakon La Leviathan, the son of the original Leviathan and Dredge's father, Cythraul Sohn Asmodeus, the son of the original Asmodeus and leader of the Old Maou Faction, and Rizevim Livan Lucifer, the grandson of the original Lucifer and Percival's father, with Drakon eventually became leader of the new Chaos Insurgency, Qlippoth before being killed by Aoqin. As of True Volume 1, Railane, Dredge, Ingvild Ryggen Leviathan, Allan and Ariel Lucifer are the only survivors among the known descendants of the original Satans, with the remainders being killed in battle and Percival sealing himself to battle 666.

During the war against Qlippoth and Trihexa, five of the seven Satans sealed themselves with the legendary beasts, leaving Myrddin and Bonnibell as the sole Satans remaining in Hell.

Trivia

 * Azazel stated the reason why more than half of the 72 Daemons went extinct in the Great Mythology War is due to the ideas and ambitions of the Original Satans which is what Creuserey mention in Volume 6 to become Kings of the World while annihilating all Seraphs, Vampyres, Heroes and Fallen Angels.
 * All seven of the current Satans have legendary creatures in their group/peerage.
 * The current Seven Great Satans are not allowed to have a harem.
 * The surname of the current Seven Great Satans will not be inherited by their offspring and that surname is more like those of managerial titles as shown in Kason and his son Millicas' case.