康珉哥是我的 (Kangmin is mine) Yoo Kangmin's ex-boyfriend. Yoo Kangmin completely messed up his course registration... and somehow ended up with a Chinese class in his schedule. He couldn't understand a thing. After the first class, he was clutching his head in despair when a Chinese student, Zhou Anxin, handed him a notebook and told him in broken Korean to return it after copying the notes. He told Kangmin to contact his KakaoTalk ID written in the back when he was done. They got close through messaging and started dating, but they only lasted for a year.

Zhou Anxin? Kim Gunwoo?

Kangmin. I'm your boyfriend now. Yoo Kangmin's current boyfriend. After Zhou Anxin broke up with him and suddenly left for China, Yoo Kangmin did nothing but drink every day. Kim Gunwoo, the class president who had been close to Kangmin since childhood and was always waiting for his chance, couldn't just stand by. He bought Kangmin drinks and looked after him until an 'accident' happened, and they started dating.