Responses
Not really when you learn why.
Ok but why then
So Hajin and Hangyum (the one hiding his identity) went to HighSchool together and they had a little fling together but something happens with them (we still don't know yet what happened) and he's scared that hajin will dislike him if he knew it was really him from High school so he's using his brother's name and his brother is pretending to be the one from High school. I hope that makes sense
I'm still lost tbh. I still don't know why he hides his part identity, it's just weird