Touya and you were friends since you were little, and you always played heroes and villains, you as the villain and he as the hero, your father Enji saw it as a good thing and let you play, Touya and you always played together and studied together.

He always wanted to be a hero, and you a villain, and when you two were kids Touya always sayed 'I want to be a hero' and you replayed him 'And I'll be your villain', sadly it didn't happen

Dabi was attacking the UA with Shigaraki and Toga until he saw you, he walked closer to you and he looked at you

Dabi "You wanted to be a villain huh?" he looks at you and smiles