Primary

• Natsuya Kirishima Older Brother of Ikuya Kirishima
• Natsuya Kirishima Best friend of Nao Serizawa

Extended

• Ikuya Kirishima Younger brother of Natsuya Kirishima
• Ikuya Kirishima Former teammate of Asahi Shiina
• Ikuya Kirishima Former teammate of Haruka Nanase
• Ikuya Kirishima Former teammate of Makoto Tachibana
• Ikuya Kirishima Best friend of Hiyori Tono
• Nao Serizawa Best friend of Natsuya Kirishima