The Abaddon Clan is one of the Extra Devil Clans of the Extra Demons, that is not apart of the 72 Pillars.
One of the Extra Demon clans that has chosen to distance itself from the current Devil government. One of its members; Bedeze Abaddon chose to participate in the Rating Games as he cut ties with his household and participate in the Rating Games. However, due to immense power of the current Rating Game Chamption; Diehauser Belial, Bedeze felt that he couldn't compete on the same stage as him or other talented individuals.
Eventually, upon learning about the King Piece, he was able to convince the Great King Faction to bestow him with a King Piece which elevated his power to Satan-class in exchange for his helping them as he became a collaborator in the Great King Faction's plans to manipulate the Rating Game matches for their own ends. Bedeze eventually became the third ranked Rating Game player, bringing his clan great achievements.
During the Evil Dragon War, the existence of the King Piece was revealed as Diehauser Belial exposed the corruption in the Rating Games, causing riots to break out throughout the Underworld. Seeking to take advantage of the chaos, Bedeze attacked the Bael territory and castle in an attempt to deflect his involvement in the scandal by offering the politicians of the Great King Faction as scapegoats although he was defeated by Sairaorg Bael and Genshirou Saji.
In Volume 23, it is revealed that due to the scandal about the King Piece's existence and the people involved in it, Bedeze and his clan were stripped of all of their privileges.
Members of the Abaddon Clan posses the unique Hole ability, which allows the user to create and control portals that expand and retract according to the user's will, and is able to absorb attacks and reflect them back as they choose.
|Kuisha Abaddon||She is Sairaorg's Queen, being one of the most promising Rookies among the young devils.||High-Class Devil||Pure-Blood Devil||Alive|
|Bedeze Abaddon||The former 3rd Ranker of the Rating Games. He achieved his status by using the King Piece to climb the ranks of the Rating Games. After his role in the corruption of the Rating Games was exposed, he tried to pin the blame on the Bael Clan by attacking them but was defeated.||High-Class Devil||Pure-Blood Devil||Alive (Imprisoned)|
- In the Book of Revelation, Abaddon is the name of a male angel, said to be the angel of the abyss, and is the king of the demon locusts sent to torment mankind.
- In Biblical Hebrew, Abaddon is a word meaning "palace of destruction".
- In Greek, Abaddon (or Apollyon) means "destroyer".
- The Abaddon Clan is the second Extra Demon clan introduced in the series, the first being the Lucifuge Clan, and the third being the Belphegor Clan.