Ryukai is a b-shot born separately in Eastern, Chrome City. He is the eldest son of Ryan Shima and Raine Kuromi, the older brother of Ryuken, Rimai and Rinne, Gyro and Tsukasa's niece. He started abroad when 11s for music.
He is the leader and vocalist of a famous indie band, More-Than-True and an under-studying musician for Chrome City. He started the band after meeting Hiro and Shurato along with Ryuken a years ago. He partnered with Viper Helios who’s evolved to Cyborg Helios then Helios MK2, a b-daman received from his mother.