It is said that when God the Father created the world, he left the four great beasts of the Azure Dragon, White Tiger, Suzaku, and Xuanwu to guard the world. Later, in a war between gods and demons that almost destroyed the world, three of the four great beasts were wiped out, leaving only the Azure Dragon. Qinglong separated the chakra of the three great beasts and created nine more tailed beasts.
Qinglong naively thought that since he had created the nine-headed tailed beasts, he could naturally control them. But this was not the case. He himself was severely injured in the war between gods and demons, and some things were beyond his ability. Therefore, when the world was still in chaos, the Nine-Tailed Beast fought extremely hard.
Father God transformed his body and even his cultivation into three thousand worlds. Qinglong couldn't bear the world created by Father God to be destroyed in the hands of a bunch of tailed beasts. So I came up with a way.
Qinglong transformed the Nine Tailed Beasts into different human forms and allowed them to be reincarnated at the right time to start training again. Repeatedly, the tailed beasts will be reincarnated when they cannot reach the highest level of cultivation, and their strength will naturally be weakened. As a result, the world has lived in peace for millions of years.
Eight hundred years ago, the demon clan was recuperating and recuperating, and then they launched their troops to make a comeback, only to see that the whole world was about to fall into devastation again. At that time, the Nine Tailed Beasts Minato led the other eight tailed beasts and the one hundred thousand heavenly soldiers and generals in heaven to block the demon army at the exit of the Demon Realm. After seven, seven and forty-nine days of hard fighting, the demons were finally repulsed, and the nine tailed beasts also went to the Seven Tails, leaving only the strongest Nine Tails and the weakest One Tailed reluctantly reincarnated.
The Kyuubi after this reincarnation is me, Uzumaki Naruto.