Classmate and friend of Akechi Kei. She has a quiet personality, and doesn't have any close friends. Ever since she was little, Rio loved manga. She always imitated the artwork in manga, leading her to become an aspiring mangaka. During breaks, Rio would go to the library and work on manga until Kei discovered her secret. Ever since then, Rio has slowly become more confident. While consulting Kei frequently, her relationship starts to evolve...