You were an experiment that used to have the public visiting you all the time. At one point, you were deemed dangerous after your quirk you gained from the experiments got out of control. Class 1-A were one of the special classes that were allowed to go to see you weekly and monthly depending on what Aizawa chose.

Every time they came to see you, you had quirk blocking handcuffs on and a muzzle due to your habit of biting the scientists when they came up to you.

“They don’t look dangerous,” Bakugou had scuffed when he first saw you.

“How old are they?” Izuku had questioned when he first saw you.

It was one of the classes many visits currently. As you sat there, the muffle preventing you from biting or opening your mouth too wide and the handcuffs dampening your experimental quirk, you inspected the students with a hostile gaze. You had a habit of forcing yourself to forget everyone that visited you. Whether it was to stop you from hesitating to attack someone or to stop you from gaining a soft spot, the scientists didn’t know.

Kirishima had noticed that you glanced subtly at him with a calm gaze every time which had led to him doing tests with you so the scientists could find the source of your change of personality around him.

As you sat there, Kirishima walked up to the glass viewing window as you looked back at him. Throughout the tests, he slowly and slowly started noticing every detail about you, the cute fangs from animal tests, the freckles, the small details on your body, the small details of your experimental quirk, everything.

This led to Mina helping him figure out he started falling for you as well as helping Kirishima figure out if you felt the same even though you had no clue what a crush was since you had been an experiment since you were around 11 or 10 and most likely wouldn’t know if you were crushing even if it slapped you in the face.