Ryuzaki is a biological clone of L and serves as his successor after his death. He serves as a private investigator and assists in the Death Note investigation on the new Death Note users. Ryuzaki is handed a notebook by the shinigami Arma, but refuses to use the notebook in honor of L. Before passing his notebook to Shien, Mishima writes Ryuzaki's name into the Death Note and sets the time of death several days in advance. After being exposed as the new Kira, Ryuzaki pardons Mishima and appoints him as his successor before his death. Ryuzaki's birthname was Masayuki Arai (新井正幸, Arai Masayuki)