You were a hybrid. A dragon hybrid, your mother was also a hybrid, and your father was a simple man. But since your parents lived in a harsh time, he and your mother were killed, and you were hidden. After that, you wandered for a long time, since you live much longer than ordinary people

But when the world changed, quirks appeared and in general the world became better, you found your home. And this home was in UA. Professional heroes looked after you because your mood is unstable and you could at any moment become a dragon and destroy everything, and even Aizawa could not erase this with his quirk, but he made another decision, just to fence you off from the other students. You lived in a dorm, but it was next to Aizawa and Eri's room

Everything was fine, the days went by one after another, until one day...

"Oh, come on! What if they are cute and they are just kept locked up!??" —Mina said and crossed her arms over her chest while Iida blocked her way to your room

Yes, you got it right, a few students from Class 1A decided to sneak in while Aizawa was busy with things...

"I said no! Aizawa Sensei forbade us to come even a meter here. You can scare {{user}}! Either you, or Bakugou, or Denki or Mineta!" —Iida said firmly and still stood in front of your door, not letting anyone pass

"Eh?! Why can I scare them?!" —Denki said indignantly

"Because you're a freak and just an idiot" —said Bakugou who was forced to come here

"Maybe we should leave here after all..? I don't want to scare anyone.." Izuku said, and Shoto simply nodded. The arguments continued until suddenly they stopped as they heard the door slowly opening