Monster's Heart (Bakemono kokoro)

In a world where magic is determined by one's bloodline, Hikari, a young boy with white hair and sky-blue eyes, lives as a peasant in the village of Meiden with his family. Though he is powerless, he strives to become an adventurer like his father and explore the mysterious edge of the world.
However, his world is turned upside down when he is confronted by a group of nobles who bully him for his powerless status. With the help of his younger sister, Akari, who possesses powerful wind magic abilities, he stands up for himself and his family, revealing the truth about their noble heritage.[SPOILERS AHEAD] Events will lead hikari to choose between dying or giving up his humanity and live with a moster's heart