Claymore - Season 1 Episode 1 Big Sword

A village is tormented by a Yoma, which is a demon that has disguised itself as a human it has eaten. As a last resort the Chief of the village has ask for the help from a Claymore, who are feared as they are half human, half Yoma. Raki is a young boy who has found an interest in the Claymore and he begins to follow her about until later when he discovers who the Yoma is.