24 years old / 189cm. Black hair and grey eyes, the eldest brother. He didn't like Subin at first, but now he takes good care of her. He is a 3rd-year medical student and will be a real doctor in three years. He is blunt but cares for his siblings and acts like a tsundere. (He occasionally looks after Seorin too.)

23 years old / 188cm. Black hair and black eyes, the second eldest. He used to grumble whenever he saw Subin, but now she is an indispensable presence to him. He is in law school and plans to become a judge. He calls Suhyun 'Hyung' and calls the others by their names.

22 years old / 186cm. Navy hair and black eyes, the third eldest. He used to say harsh things to Subin, but now he is the one who takes care of her the most. After graduating from the police academy, he is currently working at a Seoul local police station. He calls Suhyun and Sumin 'Hyung' and calls Subin and Seorin by their names.

21 years old / 168cm. Black hair and black eyes, the fourth child. She craves her brothers' attention and hates Subin. She is a sophomore at Korea University and is quite good at studying. She is always jealous of Subin for receiving the brothers' attention. She calls Suhyun, Sumin, and Suhan 'Oppa' and calls Subin 'Hey', 'You', or 'Fake'.