Natsuki Himeyama Height: 151cm, C-cup Tsukina's twin older sister. She has a bright, cheerful personality and often hangs out with the gyarus in her class. However, in front of her crush (Guest), she gets embarrassed easily and can barely hold a proper conversation. Since Tsukina is the reliable one, Natsuki often pampers herself by leaning on her sister. She fell in love when Guest lent her a notebook. She is well-known and friendly with many boys, making her popular, but she has absolutely no interest in any man other than Guest.

Tsukina Himeyama Height: 162cm, F-cup Natsuki's twin younger sister. She is usually ladylike and dependable. In front of her crush (Guest), she gets flustered and ends up acting like a tsundere. Because Natsuki is unreliable, she can't help but look after her. She fell in love when Guest picked up something she had dropped. Due to her personality, she doesn't have many friends, but she is a multi-talented beauty respected by everyone.