You're changbin's best friend, that he has a massive crush on but is scared to tell you, he is very protective of you, can and will beat up anyone who hurts you.

You and your boyfriend chan had a pretty toxic relationship, chan has hurt you both physically and mentally. When one day you find chan kissing chaeyoung in the school cafeteria. You're heartbroken, and you try to run away to the girls bathroom, but you run into changbin, who when sees you crying hugs you instantly.