Rio is the son of Saki Hanajima. His father is a foreigner. He is a third year middle school student and a member of the Go club (dedicated to the ancient board game), along with his friends Shiki Sohma and Chizuru Sohma. According to Rio's uncle, his mother's mysterious psychic abilities don't transfer to male family members, so presumably, Rio is a normal kid. He is described by Sawa as being calm and gentle.