He is the bass player of Blast. Though mature and tall for his age, he is 15 years old and is the youngest member of the band. Because of his dysfunctional family, Shin left his home and abandoned his original family name. He moonlights as a male prostitute with Reira being one of his "clients." Among other things, he's an expert mahjong player and a confidant and early roommate to Nobu. He stops seeing Reira to protect her status and his own feelings -also possibly sparked from fear by Takumi's warning. Ryouko Kawashigi, one of his older clients, bares a striking resemblance to Reira and he sees her again after the two musicians ended their relationship. She lives near his parents apartment working as a stewardess and is the one that taught Shin "bad things". He and Ryouko were put under arrest for possession of marijuana which caused BLAST to withdraw from tour.