Hazuki Shimada is the younger sister of Minami Shimada and a student in fifth grade who is friends with both Akihisa Yoshii, who, she calls "Baka no Onii-chan" and Mizuki Himeji, who she calls "Kirei no Onee-chan". She met Akihisa and Himeji through an incidental meetup at a toy store, where she wanted to purchase a large Noin teddy bear for her sister, who secretly wanted it. She kissed Akihisa on the cheek (which she calls her first kiss) and swore to be Akihisa's wife in the future.