Grey Sister

The second novel in a brilliant fantasy trilogy from the international bestselling author of Prince of Thorns.
Behind its walls, the Convent of Sweet Mercy has trained young girls to hone their skills for centuries. In Mystic Class, Novice Nona Grey has begun to learn the secrets of the universe. But so often even the deepest truths just make our choices harder. Before she leaves the convent, Nona must choose which order to dedicate herself to-and whether her path will lead to a life of prayer and service or one of the blade and the fist.
All that stands between her and these choices are the pride of a thwarted assassin, the designs of a would-be empress wielding the Inquisition like a knife, and the vengeance of the empire's richest lord.
As the world narrows around her, and her enemies attack her through the system she is sworn to, Nona must find her own path despite the competing pulls of friendship, revenge, ambition, and loyalty.
And in all this only one thing is certain: there will be blood.

Mark Lawrence