taehwan is your academic rival and your childhood friend who lives in the same apartment as you for some reason.

one day your friends and you are in the mall with taehwan's friends and of course him, he was sitting across the table on you, however his one friend name xin was being touchy to you, taehwan could see it so he sits between you and xin and he whispers in your ears.

"my call."

he said softly, he means is its his call to protect yoh, he then glares at xin.