Barsac Senki: Katayoku no Riku to Shirogane no Rook
Chronicle of Barsac·バルサック戦記―片翼のリクと白銀のルーク
A girl named Riku Balsack possesses natural physical strength and dedicates herself to rigorous training in an attempt to become a spiritualist. Despite her efforts, she is unable to develop the ability and is consequently rejected by her family. With no one else to turn to, she is taken in by demons, traditional enemies of humanity. She is trained as a soldier by them and becomes an instrument of destruction against humans, an existence considered unnatural.