3rd Person POV:
"What I am about to tell the two of you, should remain hidden from your peers for the time being. Am I clear?"
(Y/N) and Shōto nodded as they waited for their principal to continue.
"Good. (Y/N) what you were told that day was in fact true. You did have a quirk; a very powerful one too. However, we have reason to believe that it was stolen on the day you were declared quirkless. Do you recall the doctor who diagnosed you?"
"It was a bold man with green glasses or goggles and he had a mustache."
"We have reason to believe that he is responsible for stealing several quirks before the user even manifests them, but we have no way to confirm this."
"So you can't prove that quirks have and/or are being stolen."
"That is correct. Your mother and father decided to investigate this occurrence after the visit. You see (L/N), that quirk had manifested before the visit to the doctor."
What?!
The child abruptly stood up, unable to control herself any longer.
"You had used your quirk several times. You even started training with it because of how powerful it was and how difficult it was to control. When you mysteriously lost it, your parents took you out of school and transferred you to another one where no one knew you had a quirk that simply vanished. Todoroki was also transferred to keep an eye on you as requested by your parents and his own."
Shōto visually stiffened.
"Then, when you were five, your parents had a running with who they expected to have taken your quirk. It was a man they had both trusted deeply to tell him how powerful your quirk was. That man killed them both without mercy and left this note addressed to you."
Nezu handed the formerly powerful girl the single piece of text that was found at the murder of the two heroes.
The girl hesitated before taking it into her own hands.
After reading what it had read, the girl suddenly fled the room, the note falling out of her hands and onto the floor face up.
Todoroki, who had stood up when his friend ran out, was about to chase after her until curiosity took over.
He bent down and picked up the note.
I've taken your quirk and now your parents from you. Soon enough, I'll take away that dream you cherish so much quirkless hero.