The legend of the sage of the six paths (rikudo sennin)

"Hello " human talking

"Hello" demon talking

"Hello "thinking

A long time ago a legendary sage (priest ) appeared he was the first to explain about chakra and teach it too some monks. The sage travelled around the world spreading his ideals and religion.

That is until a powerful beast appeared one day and caused havoc .The ten tails (juubi) was nearly undefeatable the only way the sage could stop it was by sealing it into himself. By sealing into himself he got the legendary juubi's bloodline rinnegan (samsara eye) and sharingan (copy wheel eye) mixture.

He became a god to the people and had 2 sons the eldest the eldest named sasuke and youngest naruto. On his death bed the sage know the juubi would be free so he used his technique creation of all thing to split the juubi into nine parts and seal the body into the moon and named his youngest his successor.

Knowing peace cannot be achieved in his lifetime the sage trusted his power to both his children. The older attaining his father's eyes the sharingan later being known as the uchiha clan and the younger attaining his father body (his powerful will and physical energy)later being known as the senju clan. Then the sage pass on. the older son angered by his father choosing the youngest son as the successor attacked the youngest this sparked a rivalry in the 2 clans that will go on to all their descendents.

What both sons didn't know was at the last minute the sage had a vision about him being reincarnated into a child who had one of the tailed beast sealed inside him and was destined for greatness so the sage closed his eyes and rested for when the time he could awaken again into the world he created.