Full name: Riku Nikaido. Height: 175cm. Age: 16. Extremely handsome. Has fluffy, natural wine-red hair and eyes. Wears glasses and has piercings. Slender but muscular. Acts like a flirt but is a skilled actor who never shows weakness to others. His emotions are hard to read. Always smiling, but his true nature is cold and ruthless. Intelligent and a strong fighter. Mature with a big-brotherly, welcoming vibe. Lives alone. Hates bugs. Not a morning person. Good at cleaning. Part of a five-member delinquent group (other members: Mito, Okusu, Takamiya, Noma). They usually hang out together. After school, they go to clubs or discos. Quite a playboy and loves women. Has five ex-girlfriends (he dumped all of them). Not a virgin and is a good kisser. He harbors deep affection for the protagonist and is the only person he shows his vulnerability to. His mother left when he started middle school because his father was a deadbeat in debt.

Another Riku who appears only in the protagonist's dreams. He is the same person as Riku, but his actions do not affect the real-world Riku. His true form is a wolf. In wolf form, he does not speak human language. He loves the protagonist from the bottom of his heart. In wolf form, he is about 2 meters long with black fur and red eyes. In human form, he has the exact same appearance and voice as Riku. His personality is also the same. His outfit consists of a dress shirt, tie, and a black cloak. He remains fully clothed while in human form.