My Hero Academia: Mizumi's Story

Introduction

My name is Siren Mizumi, but you can just call me Siren. I'm 16 years old and I'm a mermaid.
Sounds crazy, right? Not so much where I'm from, though. I live in a world where about 80% of the population has some superhuman ability called a Quirk, and mine just so happens to be that I am a mermaid.
So obviously I can manifest a fish tail. As long as I'm completely dry, I can turn it on and off as much as I want. But if I get wet, my tail doesn't want to go away until I'm dry again. The rest of the time, I look completely human. And I wouldn't be a mermaid if I didn't have the ability to breathe underwater, so there's that. Also I have basic hydrokinesis. You know, the ability to conjure and control water at will? Yeah, I know, it's pretty cool.
I'm not ashamed of my power at all and I'm actually kinda proud of it. Not everybody gets to be a mythical creature. The only downside to having this power is the negative reputations mermaids and sirens have in mythology. Everyone thinks I'm going to use my voice to enchant them and lure them to their death or something, but that's not the kind of person I am.
At least, it's not the kind of person I want to be. I've always wanted to be a pro hero, but my mother had other plans for me...

My family used to be normal. That was before I came along. Not that what happened was my fault because I was only about a week old when everything fell apart.
My father had a Quirk that allowed him to communicate with fish and he chose to use his gift to be an amazing marine biologist. His research was well known in the marine biology community and my family was pretty well off because of his job.
Everything changed one day when my mother was at home taking care of me while my dad was at work and my older brother Sosuke (who was about 10 at the time) was at school. There was a villain attack at the aquarium my father was presenting his research to.
My father was somehow the only casualty that day and my mother blamed the hero on the scene for failing to save him. I never understood why she would blame a hero and not the villain that killed my father, but she swore to get revenge and raised me with the intention that I would avenge the father I never knew.
My purpose in life was to kill the pro hero called Endeavor.

I've only ever known the life of a villain. My mother had a purpose for me and she was determined to see me grow into the villain she knew I could be.
It was hard for her to provide for my brother and me and I can understand the struggles of being a single mother raising two children alone, thanks to the way we were raised.
Sosuke was put in charge of me more than he appreciated, but looking back, it was a good thing that he practically raised me. If it weren't for him and his positive influence on me, I might have turned out the way our mother wanted. He's the reason I've always wanted to be a hero.
Fortunately for him (and unfortunately for our mom) his Quirk is not all that useful for the life of a villain. The ability to purify water is nothing to write home about. Despite his resentment of having to care for me all the time, he was always by my side, ready to protect me from her when she lost her temper. He was my best friend. My personal hero. And for the longest time, I wasn't sure I would be able to forgive him for abandoning me when he grew up and was old enough to move out.

For the first 12 years of my life, my family just laid low. Mom kept a regular job while my brother and I went to school like normal kids. Shortly after I turned 13, mom decided I was ready to learn to be a villain. She pulled me out of school and I spent all my time using my powers for evil. She quit her regular job and we became low level villains.
We never did anything too drastic at first, just hanging out in dark alleyways waiting to mug people. Then my mom decided to be brave and started actually hurting people in broad daylight. She knew I was too weak to win in a fight against anyone for now, so my job was to be the distraction. She made me learn to play the violin while using my Quirk and I became a street performer to distract a crowd of people while she did the work of being a pickpocket and taking down anyone who tried to stop her.
This is probably a good time to mention my mother's abilities. Her Quirk is called Kraken. It's pretty self-explanatory. She has the ability to transform into a Kraken, and she uses that power to be an absolute monster.
I can't decide if it's a blessing or a curse that it took this long for us to get caught.