My Hero Academia: Mizumi's Story

Capture/Rescue

3rd Person
It was a typical day of low level villain activities for the Mizumi duo. At least that's what Siren assumed. Little did she know, her mother, Sadie, had gotten her hands on a bootleg version of a Quirk enhancing drug called "Trigger" that was going around among villains at the time. This version is a lot less safe than the original and has major negative side effects.
Sadie had brought her daughter within the neighborhood of Endeavor's hero agency, with the intention that this was the day they would exact their revenge. Before Siren could react, Sadie injected her with the drug, causing Siren to quickly lose control of herself and become completely feral. The two of them went on a rampage in an attempt to get Endeavor's attention.
Hawks was walking out of the building at Endeavor's side when the commotion started and quickly captured the feral teenager, while Endeavor took on the Kraken in a battle. Siren thrashed violently in Hawks's arms, trying to bite him so he would release her while her mother screamed obscenities at Endeavor during their battle. It wasn't long before the two of them were in handcuffs, being pulled apart from each other.
Both were taken into police custody, but were kept separated while the drug was wearing itself out of Siren's system.
Sadie was quickly placed into a high security prison while the Hero Public Safety Commission decided what to do with the child. Since she had technically done nothing wrong and was only a villain by proxy, it was decided she would be put into a program similar to what Hawks was put through when he was a kid.
But first, Siren needed to be reformed with a better mentality. She had only ever known a villain's mentality and it was very obvious in the way she interacted with anyone that she had been brainwashed her whole life, and may not fully understand what she was saying.

Part of this redemption training involved putting her around other young heroes in training her own age, which leads her to being temporarily transferred into the Hero Course at UA High after about a year of being isolated from the world outside of the Commission.
This is where Siren Mizumi's story really begins.