The Ten Tails is the embodiment of the Divine Tree that lashed out at humanity for eating its forbidden fruit and taking its power.
It was long ago before the founding of all the hidden villages, during an era of endless wars between mankind, the Ten Tails existed only as a fruit tree and every that was revered as a god and to end this endless war a princess by the name of Kaguya Ohtsutsuki who people was assigned to protect and worship the Ten Tails and its forbidden fruit since it's fruit only grew every 1,000 years. One day she had no choice but to eat from it to protect her and her tribe and then on was gained with the Ten Tails powerful divine power's and with this she used to end all wars during her era this was only after she had gave birth to a son who was later written in the tablet to be named Hagoromo Ohtsutsuki and he to was also given the power of Chakra and the Rinnegan and stated to be the first born with chakra. One day the Ten Tails itself became so enrage and had it took upon it's own human and animal like form as the beast watched with it's eye at the world and seen how it looked the monstrous being was confused about humankind and in anger started to attack the world it created killing Kaguya and only to be later stopped by her son who imprisoned the beast inside himself. This thus made him the worlds very first jinchuuriki.
The Ten Tails is far different then it tailed beast counterparts it's appearance is shown to be animal and humanoid and has one giant eye that has three layers of three-tomoe Sharingan in it but a Rinnegan style form.
In the time of endless time, the Ten Tails was a monstrous rampaging beast, referred to as the 10-tails. To save the world Hagoromo performed a jutsu that would seal it inside his own body, becoming the first ever Jinchuuriki. The Juubi would eventually be free once he died so he separated the Juubi's body from its chakra. The chakra would be split into 9 separate parts which would become the 9 bijuu that are known throughout the Naruto universe in the present day. He then performed another jutsu that would incase the body in a sphere of earth and sent it into the sky, where it would become the Naruto universe's moon.
After its Chakra was separated, the 9 bijuu were scattered across the world, over time the first eight were brought under the control of the 1st Hokage, who in the spirit of keeping tensions low between the five main ninja-villages, allocated bijuu to each village. They in turn would use their own versions of the original soul sealing jutsus to create their Jinchuurikis. Madara Uchiha would then take control of the Kyuubi and fought the 1st Hokage, but still lost and was presumed dead.
Tobi's plan, in which he has had Akatsuki capturing Jinchuuriki's and extracting their bijuu for years, will become complete with the capture of the Hachibi (Killer Bee) and Kyuubi ( Naruto Uzumaki). Once he has all nine, he will be able to restore the Juubi and become the Juubi-Jinchuuriki himself, increasing his already omni-powerful Eternal Mangekyou Sharingan. This will allow him to create the most powerful genjustu, "Infinite Tsukuyomi" (Mugen Tsukuyomi), which he will place on the moon itself. The jutsu will reflect on the entire planet, making everyone one with himself.
To stop this, the five great ninja villages and the Iron Country, headed by the current Raikage, have formed the first ever Shinobi Alliance to participate in the fourth great ninja war, specifically for the purpose of fighting over Killer bee and Naruto against the remaining members of Akatsuki and the seven bijuu Madara has under his command.