The Period of Warring States, known as the "Sengoku Period". The Warring States period in Japanese history was a time of social upheaval, political intrigue, and nearly constant military conflict that lasted roughly from the middle of the 15th century to the beginning of the 17th century. And indeed a time of fighting.....politics....and slowly upcoming unification under the Tokugawa Shogunate. Although the Ashikaga shogunate had retained the structure of the Kamakura bakufu and instituted a warrior government based on the same social economic rights and obligations established by the Hōjō with the Jōei Code in 1232, it failed to win the loyalty of many daimyo, especially those whose domains were far from Kyoto. As trade with China grew, the economy developed, and the use of money became widespread as markets and commercial cities appeared. This, combined with developments in agriculture and small-scale trading, led to the desire for greater local autonomy throughout all levels of the social hierarchy. As early as the beginning of the 15th century, the suffering caused by earthquakes and famines often served to trigger armed uprisings by farmers weary of debt and taxes.
Thus, The Ōnin War (1467–1477), a conflict rooted in economic distress and brought on by a dispute over shogunal succession, is generally regarded as the onset of the Sengoku period. The "eastern" army of the Hosokawa family and its allies clashed with the "western" army of the Yamana, and fighting in and around Kyoto lasted for nearly 11 years, after which it spread to outlying provinces.
Due to this intense war, it sparked the beginning of constant wars. And the beginning of the warring states. For conquest, and dominance. Eventually, a ruler, Oda Nobunaga, an member of the Oda Clan who rose up in power under the Shogunate to bring back order to Japan. And for those who rebel against his power, died a horrible painful death.
A Battle occurred at Okehazama with Imagawa Yoshimoto and Oda Nobunaga. After the battle, Imagawa Yoshimoto was defeated and Nobunaga was considered one of the front-running warlords in the Sengoku period. As Oda clan's victory seems imminent, Nobunaga laughs until a stray arrow pierces his throat- killing him. A Year later after his death, an evil scientist who experiments on the dead and considers himself a Necromancer entraps the soul of a powerful demon inside Nobunaga's body...reanimating him back to life as a demon. Now all of Japan is on the brink of doom under Oda's new army. And will anyone or anything be able to save all of Japan, and reunite also.