Natsuki Tsugumi♀

Another one of Hiroki's childhood friends who is very little sister-like and lives in the same neighborhood. Because of her weak body, her family used to spoil her a little too much and thus, Tsugumi turned into a selfish girl. Like with Risa, Hiroki made another childhood promise with Tsugumi to get married when they're older, but it feels like neither of them want to keep it... She is also the younger sister of Yuuma.