Cast in Shadow book 1 in The Chronicles of Elantra by Michelle Sagara is 99c in the US
http://www.amazon.com/dp/B000UH5Z1W
https://store.kobobooks.com/en-us/ebook/cast-in-shadow
Seven years ago Kaylin fled the crime-riddled streets of Nightshade, knowing that something was after her. Children were being murdered-- and all had the same odd markings that mysteriously appeared on her own skin....
Since then, she's learned to read, she's learned to fight and she's become one of the vaunted Hawks who patrol and police the City of Elantra. Alongside the winged Aerians and the immortal Barrani, she's made a place for herself, far from the mean streets of her birth.