|Body||Pale, Slim, Teen|
|Personality||Cheerful, Friendly, Kind, Romantic, Watashi|
|Role||Cousin, Dropout, Girlfriend, High School Student, Lonely, Present in Flashbacks Only|
|Engages in||Daydreaming, Teasing|
|Engages in (Sexual)||Not Sexually Involved|
Koharu is Sou's younger cousin and also his girlfriend. She has been in love with him since forever but he noticed just some time before and they started going out the day before her hospitalisation. Sou promised her that they would go to a date together once she was discharged from the hospital, but her health deteriorated very quickly after that...