Check this out....
Hyuuga clan is one of the oldest clans in Konoha. They have been there ever since the establishment of the hidden village. Many years ago there was a girl from Hyuuga clan who fell in love with an outsider. She decided to marry herself to the young man despite the strong protests from her own clan. But this man was no ordinary human. In fact, this man was not a human at all. His name was Sojobo. He was the King of Tengu.
There are two types of tengus, Karasu tengu (a crow-like creature with beak and wings) and Konoha tengu (also known as Yamabushi tengu). Sojobo was a Konoha tengu. He had long nose and white hair with a pair of black wings on his back. As the King of Tengu, Sojobo possessed some very mystical powers. He carried a fan made of Fatsia leaf that could create a storm (therefore people sometimes call this type of leaf as Tengu no Uchiwa or Tengu's fan). He could teleport himself or any other things from one place to another. He could also communicate with people telepathically or even invade their minds and drive them to madness. Besides, Sojobo was also known for his shapeshifting ability. He sometimes transformed himself into human to interact with people.
Anyway, this girl from Hyuuga was in love with Sojobo taking the human form without knowing his true identity. She married him shortly after they met each other. A year or two later, she was pregnant and gave birth to their first son. Sojobo named this son Uchiha, Uchiha Madara, after Uchiwa which means fan. And of course as we know, fan also later became the symbol of this new clan.
Everything was good. Uchiha Madara soon grew up to become a very powerful shinobi. He not only inherited the Kekkei Genkai from his mother but with the Tengu blood inside him the Byakugan had evolved into an even more dreadful form—the Sharingan! This new bloodline had 2 levels: Normal Sharingan and Mangekyou Sharingan. Like his tengu father, Madara possessed some incredible magical powers. He was able to use telepathy to invade people's minds, or even teleport himself across a short distance. When he turned on the Mangekyou Sharingan (he had the normal Sharingan on 24/7 just like his Hyuuga kin), the eyes would further intensify his powers and bring him even closer to a tengu form. He had developed 3 jutsus under this state, namely Tsukiyomi (to control people's minds and drive them insane), Amaterasu (to teleport objects into another dimension).But good things do not last long. As Madara was about to reach his adulthood, Sojobo began to reveal his true intention. Sojobo didn't marry the girl from Hyuuga out of love. He was only looking for a perfect body, a container (probably to achieve greater powers), and he figured the best way was to create one with his own blood. He was planning on taking over Madara's body once he reached his adulthood. It didn't take Uchiha Madara long to find out this appalling truth. He felt a mixture of shock and anger. He felt he was being used but he wasn't going to give in such easily, at least not without a fight. But Madara knew only too well that no matter how strong he was he stood no chance against the King of Tengu. Out of desperation he sought for the legendary Bijuu—Kyuubi (the God of Fire).Kyuubi was very impressed by Madara's abilities. A secret pact was made and Kyuubi agreed to lend his power and chakra to Uchiha Madara. Soon Madara mastered the katon and he could even cast a dark fire that would burn for 7 days and 7 nights after performing the Amaterasu. But even with these newly gained powers and a huge supply of chakra from the Kyuubi, Uchiha Madara was only able to beat his demon father by a hair's breadth. He couldn't finish him once and for all but only managed to seal him up. However, the seal he used was a very special one. To break the seal it requires the Kyuubi's chakra and also not one but 3 Uchiha members who can wield the Mangekyou Sharingan. Each MS user has to cast a different MS jutsu at the same time and when the 3 jutsus--Tsukiyomi, Amaterasu and Susanoo--combine, the great evil will be unleashed. It's a tall order and Madara thought it would be enough to seal up the demon for eternity.
when the first hokage fouund out wut happend he was mad at madara since thy were best friends he taught madara wanted the kyuubi power for greed so he faught wit madara in the VALLEY OF THE END.(where naruto and sasuke faught).
I found it at a thing on youtube as the description.... I'm pretty sure it's true... It sounds logical.
