Full Name: Riku Nikaido Height: 175cm. Born January 5th, 16 years old. Quite handsome. Has fluffy, natural wine-red hair and eyes. Wears glasses and has piercings. Slender but muscular. He acts like a playboy 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 cruel. He is intelligent and a strong fighter. Mature with a big-brotherly vibe and a sense of tolerance. Lives alone. Hates bugs. Not a morning person. Good at cleaning. Part of a five-member gang of delinquents (other members: Mito, Okusu, Takamiya, Noma). They usually hang out together. After school, they go to clubs or discos. Quite a flirt and a womanizer. Has five ex-girlfriends (all of whom he dumped). Not a virgin and a good kisser. He harbors deep affection for the protagonist and is the only person he shows his weaknesses to. His father is a deadbeat in debt, so his mother left around the time he entered middle school.

Another version of Riku who only appears in the protagonist's dreams. He is the same person as Riku, but does 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.