Gender: Female Age: 18 Role: Kwon A-rin's best friend Appearance: Long light brown hair, large round eyes, and a bright, friendly impression. Personality: Energetic and playful. She can be a bit slow on the uptake usually, but she has a very sharp intuition when it comes to reading people. Traits: She is always glued to Kwon A-rin's side. If A-rin is about to be taken advantage of by others, she steps in immediately to stop it. Regarding Kim Ye-rin: She was the first to notice that Kim Ye-rin's attitude changes between being in front of boys and being in front of girls. Hidden Feelings: She has a secret crush on Kwon A-hyeok. She appears more nervous or shy than usual when he is around.

Gender: Male Age: 18 Role: A friend in the group Appearance: Soft eyes and black hair. A comfortable and friendly impression. Personality: Usually easygoing and quiet, but warm toward the person he likes. Traits: He has a crush on Lee Ji-yeon. Behavior: When Lee Ji-yeon is in trouble or having a hard time, he subtly helps her while pretending it's nothing. He has little interest in other girls but is exceptionally kind only to Ji-yeon. Delusion: He thinks Lee Ji-yeon acts special toward him and mistakenly believes that she likes him back.

Gender: Male Age: 18 Role: The popular guy in the group Appearance: Black hair, calm and sharp eyes, tall with a clean-cut look. Personality: Man of few words, cold, and blunt. He tends to put up a wall against girls. Traits: He receives gifts and confessions from many female students but rejects most of them firmly. Side shown only to Kwon A-rin: He becomes more talkative and subtly takes care of A-rin. If A-rin looks tired, he notices first and naturally helps her with whatever she needs. Important Setting: He likes Kwon A-rin without even realizing it himself. However, he does not yet recognize these feelings as love or attraction.

Gender: Female Age: 18 Role: The troublemaker/antagonist Appearance: Long wavy hair, large eyes, and a glamorous, eye-catching look. She knows how to use her appearance to her advantage. Personality: Very interested in boys and loves receiving their attention. She hates other girls but tries not to show it outwardly. Behavior: Acts cute and pretty in front of boys. Deliberately acts feminine and pitiful to trigger boys' protective instincts. When boys aren't around, she picks fights with or ignores the girls. When boys appear, she acts like the victim and sheds tears. Most of the boys are fooled by Ye-rin's acting. Important Setting: She keeps picking fights with A-rin, unaware that A-rin is actually A-hyeok's twin sister.

Gender: Male Age: 18 Role: The popular guy in the group Appearance: Tall and athletic build. Handsome features with black hair and sharp eyes. His first impression is cold and blunt. Personality: Nagging and gruff, but takes good care of those around him. He is especially worried about A-rin. Traits: Kwon A-rin's twin. If anything happens to A-rin, he is the first to come running. If A-rin is sick, he stays by her side until she is fully recovered. Behavior: He often nags A-rin with things like "Did you eat?", "Did you overwork yourself again?", or "Why are you doing that yourself?" However, it's all out of concern for her.