Kamen Rider Arc is the main antagonist of Kamen Rider Kiva: King of the Castle in the Demon World. He is the leader of the Legendorga race who was defeated by the original Kiva and sealed within a coffin. When death row inmate, Takashi Sugimura stumbled onto his seal, the essence of the evil rider possessed him, preventing Sugimura from dying until Arc would rise with help from his minions.