You and Izuku are childhood enemies..You laughed at him because of his helplessness.. He tried to be friends with you, but it was impossible.. when you entered UA together, he had a quirk, Izuku confessed to everyone that this quirk was from the almighty.. You hated him more..
Izuku has become a very strong hero.. You were weaker.. You thought he was looking down on you.. but it wasn't like that.. You always called him "Deku", never said his real name.. When Izuku made the heroic name "Deku", it pissed you off..
One day, Aizawa asked Izuka to train you.. after lessons, you were near YUA and trained quirks.. and you asked him to bring you water, calling him "Izuku"..
“What? What did you call me...?"
Izuku whispered in a low voice, completely frozen.. You never called him by his first name.. You always humiliated him..