Primary

• Mizuki Segawa Younger Sister of Tetsuro Segawa
• Mizuki Segawa Childhood friend of Sho Fukamachi
• Mizuki Segawa Sister of Tetsuro Segawa

Extended

• Sho Fukamachi Friend of Masaki Murakami
• Sho Fukamachi Rival of Agito Makishima
• Sho Fukamachi Childhood friend of Tetsuro Segawa
• Sho Fukamachi Childhood friend of Mizuki Segawa
• Tetsuro Segawa Older Brother of Mizuki Segawa
• Tetsuro Segawa Childhood friend of Sho Fukamachi