Now till end of series
PLEASE READ THE ENTIRE THING BEFORE COMMENTING.
OKAY YES I KNOW THIS SOUNDS A LITTLE OUT THERE BUT HERE ME OUT.
All right the battle with the Juubi concludes with the Juubi being sent to anothe dimention by Kakashi and Obito (who has a change of heart or something) then Madara is defeated by the Allied Shinobi forces and the five Kage (Plus Naruto and Killer Bee obviously).
Then Sasuke shows up, long story short while Sasuke was off talking with whoever he needed to talk to, he came to the conclusion that the whole world and the way the Shinobi System works, is the ultimate reason his brother suffered. He becomes convinced that in order to make his brother sacrifice worth something he needs to bring the world to peace through power, he somehow releases the 10 tails and using whatever method from whoever, to bring it under his control and then captures in drains the 8 tails causing the Juubi to transform closer to its original state (in the flash backs with the SO6P the Juubi was shown to have legs).
He then reveals to the entire army the truth of the entire Uchiha clan massacre before taking off with the 10 tails sense he has trouble controlling it.
He has decided to destroy all of the Shinobi villiages with its power and force the world to Peace.
But Sasuke has trouble controlling buying Naruto time.
Naruto learns from the Kuubi a great deal about the SO6P and they come up with a way to stop the Juubi. Naruto eventually confronts Sasuke and the Juubi, Naruto and the 9 tails somehow force the Juubi to redevide and Naruto also defeats Sasuke.
Sasuke can't use Juubi cause he is still having trouble controlling it.
But Sasuke's final fate is left unknown.
Okay yes I know this sounds rediculous but hear me out with my reasoning.
If the 10 tails is stopped now then it would kind of make it look lesser. And before any one goes on about Naruto soloing both Sasuke and the 10 tails I never said anything about Naruto actually fighting it. He just uses talk no jutsu or something to redivide it.
The reason I think Sasuke would get the 10 tails is that in the fight between Hashirama and Madara, Madara brought the 9 tails with him and sense this series is all about one generation surpasing the previous it just kind of clicked.
Plus if Naruto just fights Sasuke then it makes the fight less then the current one. The final fight needs to be the single most epic and feirce fight.
Plus Sasuke intends to do destroying he is going to need a big weapon to do that and to make him a bigger threat then Madara ever was.
And Sasuke's new way of thinking sort of clicks with Obito's story about the Sage's sons.
To clearify the 10 tails isn't really involved in the fight, its just what they are fighting over. Both want to get it for very different reasons (Naruto wants to redivide it and Sasuke wants to use it for his plan.)
Plus this brings all the prophecies surrounding Naruto together in one fight.