D.D.D.

Since the establishment of the Black Knight Squadron, the kingdom of Garlonia has extended its military presence to neighboring kingdoms. The kingdom becomes more prosperous from day to day. Julius and his twin brother Michael live in the slums of the kingdom of Garlonia. Julius has always dreamed of becoming a powerful warrior, like his father, and plans to join the famous Black Knight Squadron to bring his family out of misery. Luckily, an extraordinary entrance exam is organized. During the ordeal, Julius realizes that his heroes are actually demonic beings called the "Devil Devices," and he himself undergoes a strange transformation: a demon took possession of his left hand.