Nuriko first appears disguised as "Kourin" in Emperor Hotohori's harem, which Hotohori never visits except to welcome new maidens. "Kourin" was in fact Nuriko's younger sister, who died at a young age; he began behaving and dressing like her to keep her memory alive. Born in Eiyou, the capital of Konan, Nuriko possesses superhuman strength and is later granted a pair of bracelets that transform into strength-increasing armbands by Taiitsukun. He is 18 years old. His true name is Ryuuen Chou, based on the star Willow.

While prone to jealousy, quick to anger, and possessing a calculating tendency, Nuriko is very level-headed and compassionate and shows the most concern regarding Miaka and Tamahome's relationship. As a "woman," Nuriko is infatuated with his fellow warrior, Hotohori, but as a man, he also loves Miaka Yuuki. While initially jealous of Hotohori's love for Miaka, Nuriko and Miaka become close friends. After Nuriko comes to terms with the fact that his cross-dressing resulted from the unyielding pain of losing his sister Kourin, he concludes that he had been trying to live his life as Kourin would have, not as he would have. This revelation allows him to finally allow himself to experience life as a man. He cuts his hair, which once hung down to his waist in a braid, and admits to Tamahome that he loves Miaka as more than a friend. While he maintains his feelings for Hotohori, Nuriko eventually chooses to stop dressing as a woman in order to better protect Miaka.