Kyosuke doesn't recall the faces of his parents as they divorced when he was young. He only remembers being with his older sister, and they lived together in a small village. His sister juggled with being an university student and various part-time jobs to support them. Kyosuke also worked to lessen the burden on his sister. One day, his sister brought to their home a man who introduced himself as Osaki. The fifteen-year-old Kyosuke didn't trust this mysterious new man and ran away from their home to be alone. Osaki followed him and told him to return before his sister worried. As Osaki offered to bring the boy to his feet, he unleashed a wave of power that frightened Kyosuke. Osaki, who was impressed with the boy's hidden power, manipulated Kyosuke's sister to eventually become their brot