The game takes place some fifteen years after the defeat of Oda Nobunaga at the end of Onimusha 3: Demon Siege. Nobunagas vassal, Toyotomi Hideyoshi, takes control of the country, unifying it under one banner and essentially ending the wars that had torn the land apart under his former lord�s banner. However, this period of peace ends with several natural disasters acting as an omen of things to come including the appearance of an Omen Star in the sky. The genma return to japan due to all of the natural disastersand prey on the innocent. Hideyoshi ignores all of the chaos sweeping the land. In addition, Hideyoshi sends massive armies of men and genma to invade the asian continent over seas. Two years hideyoshi uses the genma armies to gather �cherry trees� across japan.