Synopsis: The Book of Lagier

When a useless human prince enters into a pact with an almighty Demon King, the prince perishes without delay, and the Demon King is compelled to supplant him. However, there is a further complication - now occupying the body of Prince Lagier, the Demon King must carry out the prince's ultimate desires, or risk losing his previous form forever. Accompany the Demon King and his cohorts as they train, engage in conflicts with Angels, and strive to finish their assignments before their time runs out.