If you like your heroines vicious and clad in a habit, please read Red Sister, the first in the Ancestor trilogy by Mark Lawrence.
Nine-year-old murderess Nona Grey is rescued from the gallows by the Abbess Glass. Nona soon finds that at the Convent of Sweet Mercy, some girls serve the Ancestor by praying; others hone their craft as psychics, poisoners, spies, and warriors. But do they truly serve the Ancestor, or are they pawns of dark politics and magic?
Pick up this series now before the second book, Grey Sister, comes out in April.