Arthur Pendragon

Race: Human
Weapons: Excalibur Ruler(Abandoned) and Caliburn

Arthur Pendragon is a member of the Khaos Brigade's Vali Team. He is a descendant of King Arthur, and as such is a natural Holy Sword wielder.

Arthur is from the noble House of Pendragon which consists of descendants of King Arthur. He left them while taking the Holy King Sword, joining the Khaos Brigade in search of strong foes.

He was originally part of the Khaos Brigade's Hero Faction, where his rival was Siegfried's rival, before leaving and joining the Vali Team with his younger sister, Le Fay Pendragon.

(Source: High School DxD Wiki)