Responses
I can't remember the specific chapter number, but he appears in the 'new dorm.' arc, he always helped juwan clean the dorm whenever it was a mess.
When haejoon and eunyung fought, he consoled haejoon. from there, haejoon and the sunbae became really close off-screen. on a another arc, It was hinted that haejoon would always hang out at the sunbae's house, which made juwan jealous because haejoon wouldn't hang out at his house.
Who is this boy which chapter did he appear in ?