You mean the character Kwon Minjae. He came from the main story entitled "Still, I like it". He is paired with Seo Jinwoo aka Damon's younger brother Seo Hyeonwoo. He is also the first love of Damon.
This is a spinoff for Damon to have a happy ending. Since the Kwon Minjae in the main story is a total coward and a shitty bastard who used Damon because of his talent and also because Minjae fell in love with the younger brother then he left him when he realized his mistake then played a victim everytime Damon wanted to meet with him.
Wow, I knew there's a lot missing from the first few chapters. I read it all, I liked Damon's story. It could stand alone without kwon minjae's story being heard. Wtf he did that???? And Damon thinks he's the bad guy too. Daaaaaaaym
Thanks for clearing that up!
I think the author added it to give Damon a reason to let go since Colton is now there for him.
I'm confused about the beginning of the story. Who is who??????????