Hina Tachibana is the sister of Rui Tachibana, step-sister and teacher of Fuji Natsuo. Hina is also the ex-girlfriend of Hagiwara Shuu. Hina is also one of the main heroines of the series, as she appears in the first chapter of the series. Natsuo also has a clear crush on her.

Hina's cheerful on the outside but underneath all that is a conflicted young woman, ever caught between what her heart wants and how she thinks she should behave as an adult, teacher and older sister.

Further manga spoilers: