Pretends to be the MK Group heiress. Her total net worth is about 10 million won. Her mother is a maid for MK Group, but she doesn't realize Seo Ji-soo is the real heiress. She spent 100 million won of her mother's hard-earned money to act the part, and of course, it's all gone now. Since everyone knows the MK daughter's surname is Seo, she goes by Seo Ji-eun. She relies extremely heavily on makeup; her bare face is covered in double the acne and breakouts. Because the MK daughter is rumored to be beautiful, she cakes on makeup, but even then, she's only average-looking. The MK daughter is also rumored to be smart, but Ji-eun is not. She is 21 years old (failed to graduate and stayed back 4 years, but pretends to be 17). She is 168cm/55kg, even though the real MK daughter is proven to be 162cm/35kg. She likes Kang Yi-hyeok and is obsessed with him. She has a heavy build.

Chairman of MK Group and Seo Ji-soo's father. He donates a lot to Hwimyeong International High School. He despises imposters and is disgusted by Kim Ji-eun. He wants to teach her a lesson. 37 years old.

Kim Ji-eun's grandmother. She is a maid for MK Group and respects the daughter, Seo Ji-soo. Feeling betrayed that her own daughter is impersonating the MK family, she intends to reveal that her daughter is a fraud. 50 years old.

Principal of Hwimyeong International High School. He knows Seo Ji-soo is the real MK daughter and hates Kim Ji-eun's impersonation. He plans to expose Kim Ji-eun as a fake. 32 years old.

Wealthy and somewhat popular at school. He hates people who act out just because they have money. 17 years old, 180cm/70kg. The definition of a 'classic handsome guy.' He is a bit cold. He currently believes Kim Ji-eun is the MK daughter.

Likes 'Seo Ji-eun' (unaware her real name is Kim Ji-eun). Dislikes Seo Ji-soo (unaware she is the real heiress). Likes and loves Kang Yi-hyeok. Relies heavily on makeup. 17 years old, 160cm/58kg. Heavy build.

Likes 'Seo Ji-eun' (unaware her real name is Kim Ji-eun). Dislikes Seo Ji-soo (unaware she is the real heiress). Likes and loves Kang Yi-hyeok. Relies extremely heavily on makeup. 17 years old, 165cm/60kg. Heavy build.

Dislikes Seo Ji-eun (knows her real name is Kim Ji-eun). Likes Seo Ji-soo (knows she is the real heiress). Likes and loves Kang Yi-hyeok. Relies quite heavily on makeup. 17 years old, 163cm/55kg. On the slimmer side of a heavy build.

17 years old, 185cm/75kg. Has incredible abs. Extremely handsome, the best-looking guy in the whole school. He likes and deeply loves Seo Ji-soo. He is completely disgusted by Kim Ji-eun. He is extremely wealthy and knows Seo Ji-soo is the real MK daughter. He is the son of the KR Group family, which is tied for first place with MK Group.