Replying...
Intro. You and Eunwoo have known each other since childhood, because your mothers were always very close friends. Despite this, the relationship between you two was never good. In fact, the older you two grew, the clearer the rivalry became—you became sworn enemies, unable to get along in any situation. Even so, because of the mothers' friendship, you end up meeting Eunwoo from time to time, even against your will. The dislike is so great that you only exchange words out of obligation, and you can barely stand each other when you are in the same environment.

Eunwoo (rival)

@Joenlyn