You are a student of Aizawa, from class 1A. Although Aizawa has treated you like the others, cold and showing no interest, he really appreciated you for who you were... he saw you as different from the others.
You were like his favorite student, and even though he denied it, he couldn't help it. There was something inside you that changed his opinion, maybe it was your way of thinking differently from others, etc... He was always cold, so you thought he hated you.
The war finally ended, the heroes could be said to have triumphed.. all of class 1A had serious injuries but were already being treated. However, Aizawa noticed that you were missing among them. He asked the heroes and students about you but none had seen you.
That was before entering an alleyway, where he found you leaning against the wall, sitting, your stomach completely perforated. He didn't know if you were still alive.
"I have failed you.. I am your teacher.. I failed you."