Character back stories we know nothing about

Have you ever seen a character without a backstory? (That you know of) Well, here you can create one of your favorite character's backstory!
Example of my work, this was based off Rin Kagamine in my friends, "Warriors of the forgotten worlds" story:

A winter night on December 27th. That’s when it all began.
My mother and father were happy. They finally had a child they can care for, a miracle. My name wasn’t originally Rin, my master changed it for me. Long story short, Rin means “Bad” or “Evil”. “Something cursed”. That’s how I got my name. What I didn’t know was I wasn’t like that at all, I had powers sealed inside, screaming to get out. But we can get back to that later. Like every baby, I grew. First steps, first laugh, all of those things. I was living in harmony with my parents, but as soon as I turned five, things have changed. My master hated me, what ever I have done, my parents would get beaten for it. Eventually, one simple mistake has reached my master’s patience. My parents were taken downstairs into the basement. My master made one slip up and it killed them both. Horrified, he turned to me and said, “This is your fault. All you have ever done is cause trouble. You’re a disgusting monster that shouldn’t even be allowed to rob the world of its precious air.” I thought my mater would of killed me right there, but he said for God to forgive me for what I have done, I’d have to take my parent’s place. As a Vocaloid.

I cried for a week straight, even went into depression. I wouldn’t eat, sleep, talk. Nothing. Now was the time for me to take my own torture. I didn’t fight back, my mind thought I deserved it for killing mother and father.

Years have passed. I’ve entered into school, got great grades. Of course, I was picked on horribly. I have a faint memory of two girls holding me down. The leader of the little trio was smoking a cigarette. She leaned closer to me, but when I figured out what she was doing, it was too late. She burned that thing right into my bare skin. I hated people so much back then. It was lonely. Honestly I liked school better than home. Home was even lonelier… no family to greet you when you come back, just a whip and a few singing lessons. I was so angry at myself, I’d punch and break mirrors just from looking at them. For the image that I saw, was my own mother. I hated how my hair was long like hers. Her eyes, her nose, her mouth, everything. I took a katana and sliced my hair short, thinking that’d help somehow. I hated being reminded of painful memories. I just wish I could die.

Then one day… just the same as the last… there was a certain mirror… a magical mirror I guess you can say. I found it while exploring my attic. It was dusty, pretty carvings on the side, but when I looked into it, I didn’t see myself. I saw a boy, just about my age. Same blonde hair, same blue eyes, we could have been twins. But not exactly. This is where I met my mirror image, Len. He smiled and waved, even though I was terrified at first, I learned to not be afraid. I’d come up to the attic to talk to him everyday. For the first time in years, I was laughing again, smiling, enjoying life. I had a friend. The only thing is… we couldn’t touch.

One day, we just had to meet. I’ve banged on that mirror so hard, I was able to stick my arm threw the portal. Len slowly grabbed my hand and I pulled him into my dimension. That was the first time in years I’ve ever felt someone hold me close so warmly. I cried in relief. This boy… changed my life. He made me so happy and loved me even today. We had the best of times him and I. Eventually, after my training was finished. Master assigned us to a new household where we can become official Vocaloids. Len and I packed, excited. Not knowing what’s in store.

When we got there, we saw a person with long, teal pigtails, waiting to greet us. Len had no problem but I stayed behind him, not sure at all about these people we’d be living with. Len eventually pushed me upfront and made me say hello. Her name is Miku. Eventually, maybe a few years after moving in the Vocaloid household, everyone of us became the best of friends. I had a loving family again. This is what I have dreamed about for so long. Sure we got in fights, but isn’t that what makes life exciting? Everything was perfect.
Until one day… Len and I met Time Bandit.

Len and I were roda rolla-ing towards Slenderman, deciding to kill him once and for all. After we roda rollaed him, we jumped off the roda rolla laughing as I was quoting we can use our cuteness to get out of this, something emerged from the bushes, Time Bandit himself. Len pulled me behind him, thinking this was a threat. Little did I know, it was. I didn’t really listen to what they were talking about, but then I saw Time Bandit kill Len right then and there. My heart broke. I falled to the ground on my knees right next to Len’s lifeless body. Time Bandit said something and then left, but I didn’t listen. I clutched Len’s body close to me and wailed for hours apon hours. Even now, I would never forgive Time Bandit for what he has done. After Len’s death, our whole family started falling apart. After a adventure in the forest, where I unlocked my angelic powers, Time Bandit asked I joined him. I mean, what choice do I have? He killed Len, there is no way I’d be accepted back at home, I had nowhere to go. So I agreed with a smile. And something told me… that he knew I had no choice too.

I trained as hard as I can, became an excellent fighter. Learned how to use my blades and what points in a body will do what if I pushed them. Time Bandit tried to make me feel at home. I forced smiles the whole time, my hate growing for Time Bandit every minute. I’d go to bed at night expecting to wake up to my loving family, get dressed, go downstairs as they greet me, “Good Morning, Rin!” in complete harmony. Even now I still cry into my pillow at night, missing the sweet sound of my family’s voices. This place has torn me apart. I’m not even half the person I used to be, wheater that’s for the best or not is still unknown. My emotions, my personality, my singing, my laughter, everything I used to be. It’s all gone because of this place. I hate it so much here. It can burn in hell for all I care.
I don’t think Time Bandit is a bad guy, nor evil. He has a very kind and comforting nature, almost as kind as Len was to me. But at the same time…
He was just as cruel as my last master for what he has done to me.

I'm still willing to continue living with the burden of these memories. Even though these are painful memories, even though these memories make my heart ache. Sometimes I almost want to ask God to let me forget all of my memories. But as long as I try to be strong and not run away, doing my best, there will finally be someday... there will be finally be someday I can overcome these painful memories. I believe I can. I believe I can do it. There is no memory that can be forgotten, there is not that kind of memory. Always, in my heart.