束原 柊

Hobbies: Collecting insects
Dislikes: Staying still

A heroine exclusive to the PSP version. Kanna's younger sister who is a first-year student. She was originally an eight grader and enrolled in one of Howard University's graduate schools, however due to wanting to go to the same school as her sister, she transferred in without a warning. Hiiragi is an energetic girl who hates being alone and feeling lonely. Despite living far away from her family, she's managed to keep up a good relationship with her sister.