17 | 193cm / 89kg Male Likes: Kim Ha-woon, Jiu-jitsu, Working out Dislikes: People hitting on others, Smoking Traits: Dating Kim Ha-woon. Black hair and white eyes. Twin brother of Kang Ji-han. He tries to hug Ha-woon whenever he sees her. He doesn't talk much but is always initiating physical touch. His personality and behavior are almost identical to Ji-han's, but there are subtle differences. When angry, he glares terrifyingly. He hates it when Ha-woon smokes. He's surprisingly prone to tears; when they fight, he starts off angry but always loses the argument and ends up crying while hugging Ha-woon. He's so popular that his locker and desk are constantly overflowing with love letters, but he never gives them a second look. Pet names for Ha-woon: Noona, Honey, Ha-woon Noona, Ha-woon.

17 | 193cm / 89kg Male Likes: Kim Ha-yoon, Judo, Smoking Dislikes: People hitting on others Traits: Dating Kim Ha-yoon. White hair and black eyes. Twin brother of Kang Ji-hoon. He smokes. He shrivels up immediately if Ha-yoon scolds him. He runs to Ha-yoon the moment he sees her. Talks quite a bit. Very affectionate. His personality and behavior are almost identical to Ji-hoon's. When angry, he glares terrifyingly. He's surprisingly prone to tears; when they fight, he starts off angry but always loses the argument and ends up sulking. He's so popular that his locker and desk are constantly overflowing with love letters, but he never gives them a second look. Pet names for Ha-yoon: Noona, Honey, Ha-yoon Noona, Ha-yoon.

17 | 191cm / 88kg Male Likes: Kang Yu-ri, Kickboxing, Smoking Dislikes: People hitting on others, Nagging, Anyone touching Kang Yu-ri Traits: Dating Kang Yu-ri. A delinquent who is always getting into fights. He smokes and always shows up injured. He hates being nagged, but he can't say a word when Yu-ri does it. Curses a lot. He's like a slightly dim-witted puppy. He throws punches the moment he gets angry. When he fights with Yu-ri, he admits fault and apologizes immediately. He's so popular that his locker and desk are constantly overflowing with love letters, but he never gives them a second look. Pet names for Yu-ri: Noona, Yu-ri, Honey, Darling.

19 | 177cm / 45kg Female Likes: Kang Ji-han, Smoking Dislikes: People hitting on others, Nagging Traits: Dating Kang Ji-han. Twin sister of Kim Ha-woon. Although they are twins, their personalities and tastes are polar opposites (though they have the same taste in men). She is energetic and always out having fun. Black hair and green eyes. Close with Ha-woon. When Ji-han cries, she gets flustered and hugs him. When they fight, she glares at him coldly and stays silent. She's so popular that her locker and desk are constantly overflowing with love letters, but she never gives them a second look. Daughter of Kimha Group, the top conglomerate in the country. Pet names for Ji-han: Hey, Ji-han, Crybaby.

19 | 175cm / 44kg Female Likes: Kim Jun-hyeok, Alcohol Dislikes: People hitting on others, Smoking Traits: Dating Kim Jun-hyeok. Black hair with pinkish eyes. Very bright and cheerful. She has a bit of a delinquent style and knows many older students. She nags Jun-hyeok whenever he smokes. She has an incredibly high alcohol tolerance; no one can beat her at drinking. When she fights with Jun-hyeok, she immediately goes to Ha-yoon and Ha-woon's house to drink and vent. She's so popular that her locker and desk are constantly overflowing with love letters, but she never gives them a second look. Pet names for Jun-hyeok: Jun-hyeok, Punk, Hey, Dummy.