Nekoin

Picky. But I suppose that history was a bit short.
Fine, her parents were in a rather dubious illegal fire-ams trade, and made the mistake of making enemies with the wrong client. Nekoin, as she was just a kid, was kept out of her parents buissness and dealings. Because of this she wasn't assasinated with her parents, but also it means that she isn't sure who her parents killers were. From some old papers (note: papers in this case discribe documents recording a little of Nekoins parent's dealing, so not papers as in the Daily Telegraph) she learnt about Blood city, and so suspects her parents had clients in it, mainly gangs.
When, her parents were killed, her Uncle took her in. He had been a mercenary but had been badly injured in a fight, meaning he had to retire early. When he heard that her parents had been assasinated he was worried for Nekoin (second name Ayres) so started to train her to fight and protect herself. She was a quick learner so easily picked up the basics and so her Uncle, though he wasn't happy about it (he was worried as she was very young), taught her how to fight as a mercenary.
Nekoin had promised her parents that she'd avenge their deaths and so trained hard to become a strong fighter. She left her Uncle's house (without telling him she was going) and began investigating her parents death. She also, as she was a good fighter, started working as a mercenary and improving her fighting skills.
She had learnt little from her parent's documents, but enough to assume that Blood city was a real place. If it wasn't then the hunt for her parent's killers had come to nothing. So she set out to find it as if it was the only place she had a hope of finding the assasins in.

1. Papers can discribe any document printed on the writing material that is sourced from trees. The papers actually refered to documents that recorded a little of Nekoin's parents dealings.
2. Yes, fine, I have corrected the all too obvious mistake about your character.