being related to people from Hinamizawa and once living near there, in Okinomiya. She makes a cameo appearance in Miotsukushi-hen when she attends the Watanagashi festival meeting Keiichi and the others except Satoko who's at the Irie Clinic undergoing treatment. Ooishi consistently attempts to make contact with Natsumi to find out the truth about a certain "unsolved mystery". As an elite career investigator from the Metropolitan Police Department in Tokyo, he and Ooishi solve a certain mystery. A cheerful and friendly classmate of Natsumi and Tamako. In "Onisarashi-hen" and "Someutsushi-hen", she introduces Natsumi to Akira when the former first started high school after moving to Kakiuchi from Okinomiya. In "Someutsushi-hen" she fails to get together with Akira after he chooses Natsumi over her which she feels devastated but eventually respects their relationship. While she really cares for Natsumi's wellbeing, she has a bad habit of making insensitive statements mostly regarding Natsumi's heritage by comparing her own benefits of her home city which is superior to Natsumi's countryside side which causes her to become upset quickly and Tamako has to admonish her about it. It's later revealed in Kageboushi-hen that the reason why she's strongly affectionate towards Natsumi is that the latter reminds her of Kaori, her deceased younger sister who had died from an illness that requires a bone marrow transplant to treat it. Chisato was a potential donor for it but she contemplates it when she discussed with her father who's a director for the private hospital, the Saeki General Hospital and had to see Kaori passed away from it in front of her. A classmate of Natsumi and Chisato. Unlike Chisato, Tamako is a bit silent, calm, sensitive but also an outgoing girl. She and Chisato were childhood friends along with Tōdō Akira. Later on, she befriends Natsumi and helps her out whenever Chisato jokes with her. Just like everybody else at her school, she also treats the Hinamizawan people as "freaks" after the Great Hinamizawa Disaster which puts stress on Natsumi and makes her a victim of the Hinamizawa Syndrome but unbeknownst to Natsumi, if she had confided her origins to Tamako and Chisato, they will forgive her as they are close friends after all. After Natsumi ends up in a hospital she visits her regularly along with Chisato and helps to forget the death of her family. A male classmate of Natsumi, Chisato and Tamako who