As the Overfiend emerges ahead of schedule, the fragile balance between realms faces immediate threat from the looming arrival of the Lord of Chaos. Amano travels to the kingdom of Azuma to uncover signs of this adversary, only to find himself drawn into the dictator Caesar's plans for domination while a revolt brews among the hybrid demon beasts. With the return of a dangerous old foe and the world on the brink of renewed destruction, Amano and his unlikely ally must act swiftly to protect all that remains.