1. Yulhan

Traits: Smart, hardworking, but starting to feel trapped in the conventional way of learning. Open to new ideas.

Profession: High school student, has good academic performance but is more used to the traditional and structured way of learning.

Relationship: Eunyeon's classmate, feels challenged by Eunyeon's study method. Son of a math teacher.

2. Eunyeon

Traits: Intelligent, creative, confident, and free in his way of thinking and learning. Relaxed, unaffected by academic pressure.

Profession: High school student, new to the school, very smart and has a unique way of studying, often studying at home with his father's guidance.

Relationship: The new kid in school who impresses Yulhan with his different way of studying. Has a close relationship with his father who is a professor.

3. Professor Baek (Eunyeon's father)

Traits: Thoughtful, compassionate, in favor of a more free and curiosity-based approach to education.

Profession: Professor, teaches and conducts research in a highly respected field. Taught Eunyeon to think outside the box since childhood.

Relationship: Eunyeon's father who is very supportive of his intellectual development. Became an inspiration for Eunyeon in terms of how to study.

4. Minsik

Traits: Bully gang leader, confident, dominant, likes to intimidate weaker classmates.

Profession: High school student, one of the most popular students in school due to his aggressive nature.

Relationship: Involved in class dynamics with Eunyeon and Yulhan. As one of the bullies who tries to show power in school.