

The battle was so great that it tore the earth apart and created the Valley of the End. Many decades ago, when Madara Uchiha defected from Konoha, he used his Mangekyō Sharingan to take control of the Nine-Tails, and used it to help him fight against Hashirama Senju, the First Hokage, to exact his revenge. Over the centuries, the Nine-Tails gained a reputation as an age-old natural disaster, appearing at random to attack areas where human malice has collected and festered.

The Nine-Tails first came into being in the waning days of the Sage of the Six Paths' life to prevent the Ten-Tailed Beast resurgence, the Sage split up its chakra into nine separate, monstrous constructs of living chakra, which would become known as the tailed beasts.
