Rurō Arthur is one of six individuals chosen by the sacred sword Excalibur, bestowed the title "Arthur" and granted significant power. His designation "Rurō," meaning "wandering" or "drifting," reflects his thoughtful nature. He wields twin firearms as his primary weapons and possesses distinctive grey hair and petrol-colored eyes.

Tasked with restoring the world's distorted history, Rurō Arthur engages in combat missions across England, targeting corrupt figures empowered by Excalibur. During one such mission, he became separated from the group. Danchō Arthur specifically attempted to partner with Yamaneko Arthur to locate him, but this effort failed when Yamaneko Arthur instead teamed with Renkin Arthur.