Red Sister : book one of the Ancestor

'I was born for killing - the gods made me to ruin'. At the Convent of Sweet Mercy girls are raised to be killers. Some have inherited old bloods, which bestow upon them special talents. Sweet Mercy hones it's novices' skills with care: it takes ten years to educate a Red Sister in the deadly arts of blade and fist. But even the mistresses of sword and shadow don't fully understand what they have purchased when Nona Grey is brought to their halls as a child of eight, accused of murder but guilty of worse. In her short life, Nona has made powerful enemies, and despite the security and isolation of the convent, her violent past will one day find her out. Nona must face her demons and become a deadly assassin if she is to survive... - Publishers description.