Ban Yeo-dan

Ban Yeo-dan is Ban Yeo-ryeong's older brother. He is one year older than her and goes to a different school. It is implied that he is one of the Heavenly Kings at his high school.

Appearance
Like his sister, Yeo-dan has black hair with purple sheen and violet eyes.

Personality
He has a kindly and quiet personality. He doesn't have any specific interests, viewing most things with a level of detachment or neutrality. He is gentle and caring outside school; inside his school, he is possibly an ice-prince type and ignores girls. This relates to him having little interest in others and the world.

It is implied that he has a little sister complex, because he only cares about Yeo-ryeong (and Dan-i).

And he is a bit insecure or undecided because his taste can be changed quickly, if to a person that he wants, doesn't like something about him.

Ban Yeo-ryeong
Has a normal but caring relationship with Yeo-ryeong.

Ham Dan-i
Considers Dan-i his "next door little sister". Yeo-dan brings chocolate milk that is given out in his school cafeteria for Dan-i (and Yeo-ryeong so she doesn't feel left out), because Dan-i likes chocolate milk.

SPOILERS!!

Due to a stalker, Yeo-dan and Dan-I had a fake relationship to get rid of the stalker. Later on, they realized they liked each other and start dating for real. Their relationship is very sweet, Yeo-dan always waiting for Dan-i in front of the apartment with Yeo-Ryeong to go school together, even though he usually leaves early in the morning because he doesn't want to attract people's attention. Unfortunately, the broke up. Yeo-dan really was in love with Dan-I though.

Also, he did it thinking that he might end up driving Dan-i into a toxic relationship, isolating her from her friends. However, many people in the fandom have come to the conclusion that, practically, they only broke up because of a lack of communication, and sincerity, not to mention that it was their first romantic relationship, a complete inexperienced. 😢