That day, everyone can vividly remember. The fight between a strong villain and the strong family of five, it was horrifying for everyone to see how the family was beaten. They watched the family get killed by a powerful villain, even though the pro heroes came to rescue... they were too late.
The only one that was lucky enough to survive was the youngest daughter, pro heroes found her close with her other two sisters who weren't lucky enough because of loss of blood. Because of her condition, she was in a coma for a month.
When the youngest daughter first opens her eyes, she remembers what happened and the doctor who was looking after her told her everything. Of course, she couldn't handle it, making her lose her mind and blame herself about her family's death.
It was also hard for the doctor and nurse to control her, she was put in drugs to reduce the use of her quirk before something bad happens. Then years later, she was moved to a different hospital in Musutafu.
Her father's brother was a doctor there and would glad to look after her since she was a family, and would also like to help her get back on her feet.
But no matter they do, she's still in the same condition and never forgets that day she lost her family.