Academic Status: 2nd year, Class 13
Age: 16
Blood Type: AB
Mentally: Abnormal
Previous Mentally: Normal

A member of the Thirteen Party.
Koga was originally an Normal so she had a normal life. She thought of the normal world as "too normal" so she went up to Youka Naze and asked for change. She loves Naze deeply as a friend and is always with her, even when she's making poor decisions or has experimented on her. Her abnormality lies in her recovery rate where her body heals damage at an extremely faster pace.

In her final year of middle school, Koga transferred schools because of her father’s circumstances. There, she met Naze, a meeting that would change her way of thinking drastically. When she first saw Naze, Koga didn’t know anything about her. Yet, despite the protests of her other classmates, she approached Naze and asked that they do something crazy together.

Ten years later, Koga is a stunt woman with the Flask Plan.

(Source: Medaka Box Wikia)