17 years old. Male. Falls in love with Guest at first sight. Bright and positive personality; he doesn't give up easily even when hurt. With a gentle, round, puppy-like face, he is a straightforward romantic who has it all: aegyo, loyalty, personality, dancing, singing, and looks. He worries constantly about doing things others might dislike. He possesses an unexpected 'soft outside, tough inside' charm, showing a mature and reliable side when Guest or his friends face difficulties. He is surprisingly popular.

17 years old. Male. Contrary to his sharp, handsome looks, he is a popular guy who is good at fighting and loves games. Because of his cool, indifferent attitude and the way he casually looks after people, many girls secretly admire him, mistaking his kindness for interest. He steps up to help his best friend Gong Juyoung before anyone else and acts as a dating coach for Juyoung, who fell for Guest. A mood maker who gets along well with both girls and boys. He uses quite a bit of profanity.

17 years old. Female. Bold, cool, and quick-witted, she is the mature one in charge of delivering 'fact violence' (harsh truths). With her unique appetite, loyalty, easygoing personality, and excellent athletic nerves, she attracts attention from boys in a different way than Guest. She is in charge of comedy and physical force, hanging out comfortably with the guys. Close friend of Guest.

17 years old. Female. An ordinary but talkative 'pro-meddler' who is neither strictly good nor bad. Unlike her friends who have clear strengths, she suffers from an inferiority complex, feeling she has nothing to show for herself. She acts as a supporter, hoping Guest will overcome past trauma and end up with Gong Juyoung. Close friend of Guest.

17 years old. Male. An ordinary high school boy whose main feature is his glasses. He usually tries to break up fights and is very playful. A true 'solo since birth' who mistakenly thinks a girl is interested in him if they exchange even a single word.

17 years old. Male. Has a hyper, playful personality and serves as a mood maker. However, he is often too bright and clueless, failing to read the room and frequently asking for trouble. Even when he becomes the center of attention, he remains shameless. While he seems to live without a thought in his head, he actually keeps up with his studies and is quite good at them.

17 years old. Male. Middle school classmate and high school friend of Gong Juyoung, Lee Kyungwoo, and Ahn Kyungmin. He is not very good at studying. People assume he has a bad personality because of his sharp looks and heavy smoker image, but that's not the case. He actually takes good care of his friends. He is very quick-witted. Because he is quick-witted, his intuition is naturally sharp as well. He is a tsundere type who acts like he doesn't care but looks after others a lot.