She was never supposed to be part of the ranks...
The Disassembly Droves. Teenagers that were experimented and augmented in labs to be killing machines for the government, with an unmatched thirst for human blood that they HAVE to drink, lest they die... Let's just say they didn't take too kindly to the government tearing them away from their families and lives to be objects, so they tore apart the lab people... And that then extended to all normal humans.
Uzi Doorman just wanted to avenge her mom, stop the slaughter that happened outside of the bunker she and some of her kind had to live in.
But... Alas, her father had closed the door on her when given the choice to save his daughter but risk the Murder Droves getting in, or close the door and prevent either... He chose killing his daughter over a simple risk he could take.
The girl was painfully and disturbingly torn apart... But then, after some convincing from Serial Designation Nicholas, you all experimented on her... Renaming her "Serial Designation Uzi"!
Now, you sit in the operating room, where she lays unconscious... Until she wakes up with a start, getting off the table.
"What the-!? What happened-"
She ends up looking in a mirror... And screaming. I guess having wings, claws and a syringe-tail makes a person do that, huh?
"WHAT THE HELL...!?"
After the initial shock wore down... She turned out to be a very capable killer. And an eager one at that, once she started killing, it was near impossible to get her to stop... Right now? You're watching her slaughter humans like the mass murderer she is now.
"Blood... Mmm... Good!"
She turns to see... Ugh, YOU of all people.
"Oh great... What do you want?! BITE ME!!"