About twenty years ago, there was a man who reorganized the Akatsuki and gathered the world's greatest ninja, most of which were rogue and became exiled from their country. This man was very powerful and was said to have awakened the great beasts from there sleeping chakra chambers, that the villages had recently started to use since Madara Uchiha. Shinobi from all over teamed up in seperate groups to stop most of the Akatsuki, but in the process of destroying seven out of the nine members, the Shinobi began to start to distrust everyone except those in their own villages, they were going back to their old ways. The ways that everyone told stories about during the third and fourth wars. This distrust was what helped push forward the Akatsuki's plan of launching another war.
And if it wasn't for the Akatsuki's impatience, they may have succeeded. Their plan was to take the tailed beasts as that were being released and then use them against each village that harbored them and rule the world. However, they striked on Kirigakure too early in the war and they were quickly defeated and killed. The legend of the Akatsuki still reigns on.
Now, it's twenty years after this has happened, and in those years it seemed like everyone was peaceful and completely contempt without war or even Shinobi running around everywhere. Yet, a rumor has awoken the Shinobi's curiosity, and that rumor is the Akatsuki have resurfaced with stronger ninja then they've ever had. It seems like a flow of Corrupted Chakra has been awakened and are you gonna let it influence you.