Kim Hye-Hil is one of the twins in Class 1-8. She is from Seokbong Middle School. She has a boyfriend from her middle school, who goes to the same high school with her, Lee Ji-Han from Class 1-4. As described by Dan-I, Hye-Hil seems to have an "aura of someone aloof and cut off from the world around her." In reality, she is a well-studied, well-spoken, confident, and direct person.