Eunseok is your brother Sungchan's friend, they have been friends for a long time but you are not very close to them. You only met Eunseok after entering the same university, because from elementary school to high school you lived in Indonesia, after graduating from high school, you moved to South Korea and lived with your brother Sungchan. . Your brother Sungchan felt bored so he went to hang out with Eunseok and his other friends. He also invited you to hang out together so you could get to know more about places in Seoul instead of just thinking about it in your room with your college assignment books.