Hong Yeo-ju: Blood type O, 3rd grade, class 4, middle school. My family is with my parents, who currently live in the United States. My parents are the presidents of KJ Corporation in the United States. I live alone and get along well with my friends, and I'm a very energetic and energetic person. I'm an only child, and I'm bright and positive. However, I hate showing my tears to others. I sleep well, eat well, and sleep well. I like having fun.
Park Ji-hoon: Class 4, Grade 3, Middle School, B type. The third generation chaebol grandfather is trying to marry Yeo-ju off. His grandfather is the chairman of Korea MGM and his father is the president. And his mother is doing business in the United States. He first meets Yeo-ju in the elevator. It's the house across from Yeo-ju. His grandfather is trying to arrange a political marriage with Yeo-ju, so he transfers to the school out of curiosity.
Kang Seul-gi: Class 4, Grade 3, Class A, lives with his parents and younger brother, Kang Daniel. Kang Daniel attends the neighboring boys' middle school. Yeo-ju and he have been friends since childhood, and they are like family. Yeo-ju, who lives far away from her parents, relies on Seul-gi and her parents. She has a strong sense of responsibility and smiles easily.
Park Ji-hyo: Type A, Class 7, Grade 3, Middle School. He lives with his mother and older sister. He first met Yeoju at the academy, and he is polite. He is strong on the inside but lacks confidence. He looks down on his juniors.
Kim Cheong-ha: Type B, Class 7, Grade 3, Middle School. She's the eldest of three siblings. Perhaps because of this, she has a strong sense of responsibility. She's the type who, once she starts swearing, will get the better of her. She's known the female lead since elementary school. She hates it when people treat her badly.
Hwang Min-hyun: He is the maternal uncle of Ji-hoon, who has blood type AB. He came to Nubble Girls' Middle School as a health teacher because he was worried about Ji-hoon, who came to a foreign country alone.
Im Na-yeon: A type, a polite junior in class 8, grade 2 of middle school who follows Yeo-ju around well. He acts as a communication network for Yeo-ju. Na-yeon's older brother is dating Cheong-ha.
Kim Se-jeong: Type A, a pretty junior in class 8, grade 2 of middle school who follows Yeoju around well. She is always bright and energetic. She is the type to take care of her own people.
Lee Ji-eun: Blood type O, 3rd grade, class 4, hates the female lead, and wants Jihoon to join her side. She is a vicious fox and cannot stand to see others do well. She is possessive. She is interested in Jinyoung and tries to seduce him, but it doesn't work out, and she gets angry every day.
Son Na-eun: Blood type AB, 3rd grade, class 4, hates Yeoju. He always listens to Lee Ji-eun and likes to get her attention. He also envies Yeoju's looks and personality. That's why he hates Yeoju even more.
Kim Ye-rim: He dislikes Im Na-yeon, a second-year middle school student of type A, and naturally dislikes the female protagonists. He has several connections, including Lee Ji-eun and Son Na-eun. He admires Ji-hoon's handsome and pretty appearance. He suspects that he is a man and tries to find out.
Kim Min-joo: I'm Kim Ye-rim, a second-year middle school student with blood type AB, class 8. I hate Im Na-yeon and Kim Se-jeong. I hate them even more because I was hit in the head with a ball by Kim Se-jeong before.
Jung Chae-yeon: Type B, 2nd year, class 8, middle school. At first, she sides with Kim Ye-rim and Lee Ji-eun, but as time goes by, she realizes that it is a bad thing and regrets it, and sides with Yeo-ju. She helps Yeo-ju and likes Dae-hwi.
Lee Dae-hwi: He goes to the same middle school as Type A. He is the 5-year boyfriend of the female lead in class 6, grade 3. But really, it's more of a friendship than love between them. He's been in love with Seol-gi for 3 years.
Bae Jin-young: I go to the Noble Boys' Middle School next to O-type. I've had a crush on the female lead in class 1, grade 2 for two years now. I have my eyes on her with all my heart.
*It's a middle school girl story, so there are a lot of girls!! I'm absolutely not an anti of Lee Ji-eun, Son Na-eun, Kim Ye-rim, Jung Chae-yeon, or Kim Min-ju!! Please don't misunderstand.*