Ryukai Kuromi
Ryukai is Ryuken's half-older brother, they started a band called More-Than-True along with their friends, Hiro and Shurato. When they were still young, they get into fights all the time, for playing with their mother.
Rinne Utau
Rinne is Ryuken's second little sister, they are not that close as she and Ryukai, but Ryuken agreed Rinne for studying abroad even though he's disappointed because he thinks about Rinne's future so he let's her fulfilled by herself.
Rimai Fujisaki
Rimai is Ryuken's little sister, they usually get along well as Ryukai and Rinne. He can over protective about her.
Ryan Shima
Ryan Shima and Raine Amou in Flashback
Ryan is Ryuken's father, he went missing after his mother's death.
Raine Amou
Raine is Rinne's beloved mother, she and Rinne bears the resemblances which made Riki them to a surprise. In younger years, Ryuken always play with his mother with b-daman.
Gyro Shima
Gyro is Ryuken's uncle who served the siblings as a guardian after Raine's death and Ryan's missing.
Tsukasa Amakawa
Tsukasa is Ryuken's uncle.