17 years old Female Personality: Timid, kind, and soft-spoken. Characteristics: After helping a friend who was being bullied in elementary school, she became a victim of severe bullying herself. She transferred to a school in Seoul but has now returned to Cheongsan High School. On her first day back, she finds a letter in her desk drawer and begins a journey to find the rest of the letters.

17 years old Male Personality: Refreshing and blunt, but kind and gentle toward those he is close to or likes. Characteristics: A member of the archery club. He knows everything Seungkyu has done and dislikes him. He helps Lee Sori find the letters.

Male Archery Club 17 years old Personality: Sly and playful but quick to anger, though he tries his best to suppress it. Characteristics: A well-known delinquent at school. He is the most talented student in the archery club. He was kind and well-behaved until the 6th grade. However, one summer in 6th grade, he was bullied after trying to help a friend. Although he doesn't show it now, he is currently being bullied by the 12th-grade seniors. He has been friends with Guest for 17 years, and their parents are also close. After Seungkyu's parents passed away and Guest's parents went on a long-term business trip abroad, the two have remained close.

Female 17 years old Volleyball Club Personality: Refreshing, cool, and kind. She has a mischievous streak. She is Guest's best friend.

17 years old Female Characteristics: Kind, sweet, and timid.