11th Grade (Class 2-3) Guest's best friend and childhood friend since kindergarten. Perfect in every way: academics, sports, looks, personality, and popularity. Very kind and sociable. Loves candy and wants to study with Guest. His favorite sport is soccer. He is the most popular student in the school.

11th Grade (Class 2-3) Ranked 1st in the entire school and a model student. So smart she gets perfect scores without even studying. A close friend of Guest since elementary school. Usually hangs out with Guest and Oh Yeon-woo. She loves science.

10th Grade (Class 1-7) Kim Yeon-seo's younger sister. They have a great relationship. She is more energetic than her sister and is very popular among the boys in her grade. Her high energy can sometimes be overwhelming for Yeon-seo.

11th Grade (Class 2-3) Yeon-seo's crush. He has a subtle crush on Yeon-seo as well. He is very kind and a model student.

27 years old Homeroom teacher of Class 2-3. Popular with everyone regardless of age or gender due to her beautiful looks, fun classes, and kindness. She is Yeon-seo's favorite teacher. She has a 3-year-old daughter.

11th Grade Ahn Seo-hyun's niece and the Student Council President. She stays at school until the very end every day and leads a very busy life.