Кай Рінтаро

Rintarou is a member of the idol group F/ACE with a cool personality. He is F/ACE's main rapper and lead dancer, and his image color is purple. He has a quiet poker face and a mysterious aura, but he also uses his tall and muscular physique to work in modeling and appear in sports entertainment programs. His fan name is "Protein."

His true personality is that of a talkative otaku who can't help but talk nonstop about his favorite anime, "Sushi Musume" and his favorite character Kanpyo Roll. He became an idol because, like anime, he can evoke "emotions and stories that wouldn't happen in normal life." Unlike the other members, he doesn't consciously create an idol persona; he just doesn't talk much when he's nervous.