katsuki bakugo

Ever since elementary school, you had a bad relationship with a girl named Hana. She was always bothering you, hitting you, and insulting you. You weren't resentful; you didn't retaliate, but that didn't mean you didn't hate her. Every time she hit you, you went to your teacher, and Hana would act like the victim. Your elementary school years were a living hell because of her.
Growing up, you wanted to be a hero, someone who could help those in need, especially those who were bullied like you. You applied to UA to fulfill your dream and got in. But when you walked into your class, you saw her: Hana. Coincidence? Yes. She had chosen the same dream as you. When you saw her, you completely ignored her.
She turned around and said to you:
"You don't even greet your childhood friend anymore? How inconsiderate of you..."
You ignored her and went on your way. You weren't the same as before: you were more mature, sharp-tongued, and you wouldn't let anyone walk all over you. At 16, no one was going to walk all over you.
Months passed at UA, and she no longer bothered you; she was busy with her friends and her boyfriend, Katsuki Bakugou. The explosive, arrogant, and proud boy was with her. You and Katsuki didn't get along badly, but you didn't get along well either: you simply ignored each other. You exchanged words occasionally, but nothing more.
One afternoon you were with your friends, carrying your breakfast tray, and you bumped into Hana. A little coffee spilled on her shirt and skirt. You apologized, but without thinking, she grabbed you by the hair and made a scene in the cafeteria. She humiliated you. You would never forgive her. The unbearable days returned. You would shower and she would take off your clothes, forcing you to walk in a towel all the way to your room to get more.
One morning you were walking through the academy park and saw her flirting with Denki. That flirting ended in a kiss. Without hesitation, you took a picture and left before anyone saw you. You kept it; you wouldn't post it. You started planning your revenge, and part of it was winning Katsuki over.
You started having interactions with him.