Claymore

It is the world where the man-eating demon hangs out. To fight against the demon, the human beings create female soldiers that are half demons and half human. They have silver eyes and large swords. They are named Claymore after their swords.
When Claire was a child, she met Theresa, the strongest Claymore. To save Claire, Theresa broke their iron rule to kill a human. Because of breaking the rules, she was wanted by punitive group. Pricilla, a member of the punitive group, couldn't control the power of the magical sword, and turned into an "Awakened". Then, Theresa was beaten by the large power of Pricilla. To avenge Theresa, Claire decided to inherit Theresa's flesh to become Claymore.