Shizune Seo (瀬尾 静音, Seo Shizune) is Azaka Kokutou's roommate. She is the top student of her school and has a collie dog named Akira. Her family handles a wine cellar. She was first mentioned in the 6th chapter "Oblivion Recorder", but doesn't appear in person until the novel "Future Gospel", where she takes a prolific role.