Trouble

Intro

Do you honestly think that I thought we wouldn't be caught?
Well...if you thought we wouldn't be caught you're wrong.
Of course she wasn't caught though...I don't know where she even went. She just....disappeared into thin air. Part of me wishes she was found, and caught just like us, but the other part of me is happy she wasn't. It's weird because she put us into this situation, we would be out having fun if she didn't talk to us that day. We wouldn't be going to jail, and in trouble with the law if she hadn't shown up. In the next instant we are standing handcuffed, leaning against the cop car. Looking up I noticed something. Eyes. Not just any eyes, her eyes. She's here, watching this all go down, and not doing anything to stop it. I looked at her, though since she was standing in the shadows, I couldn't see very much of her. I did see that she had her hair pulled back into a ponytail. She was wearing a t-shirt and shorts, with sneakers, and a jacket. She looked like your average athlete. When she noticed me watching her, she smiled, but it wasn't a smile of happiness or shyness, I could see it in her eyes and the way she smiled, it was a smile of chaos, or maybe revenge? I'm not sure, but it wasn't anything good. Our backs now facing the police as they attempted to file us into the car, suddenly the hands holding us in line were gone, we turned around to find the police looking around on roofs of the buildings. Within seconds we heard a crack and a thud. Turning around we saw the girl standing there over the bodies of the officers.
"They're not dead, don't worry" she stated emotionlessly as if she has hurt someone way worse, which to be honest I wouldn't be surprised by. Examining her I saw she was holding a bat. The bat looked very familiar to me. Written on it said "Good night." I know I've seen it before, but where??
"Harley Quinn, nice to meet ya" the girl smirked
I must have had a confused expression on my face cause the girl looked at me, rolled her eyes and told me what I was confused about.
"No, my name isn't Harley Quinn. I saw you looking at the bat and thinking about something, so....."
She stared blankly up at me.
"See-ya!"
She walked off, but quickly stopped, and looked back at us.
"Two things before I go,
1) You'd better leave while you can, because their backup will be here at the scene soon." She continued
"And 2) what's your name?"
I stared at her for a minute before speaking.
"M-My name is H-Hayden, Hayden Black...." I stuttered.
Cocking an eyebrow up, she smirked.
"Hmph"
And with that she left, scaling up the tall brick building, and running across the roof in only a few moments.
She left us there to wonder,
Where did she come from?, Why was I so important that she needed to protect me from going to jail?

And most importantly...

Who is she?