First off J man brings up a point with the yin and the yang chakra being separated. It sounds as if the yin has been sealed away within the death god technique, and not inside Naruto as previously thought. The death god takes both the souls of the target and the user, thus making it once it has your soul there is nothing that can be done (as of note it seems human realm is also able to take a person’s soul, but we’ll have to wait and see on that). Much like sarutobi ended the jutsu with only oro’s arms, Minato could have ended the jutsu with only the yin chakra of the fox being taken.
This would serve two uses, first it makes the death god happy because even half of the fox is a shit load of energy and probably gave him some indigestion. The second is that it gives Naruto a shit load of chakra to fall back upon when he’s in a crunch. The yin chakra is a more docile and softer version of the fox, and though it would more likely cooperate with Naruto, it would be incredibly weaker than full force. The yang chakra, which would be the stronger more violent side of the fox, would however be much stronger, probably even than full fox because the yin would be there too limit the excess of power the yang would have (almost like averages).
This would give naruto unbelievable energy, but it is unconstrained as one can see when Naruto goes four tails. This means that if there were any way to control this chakra it would be stronger and more powerful than the original fox because it lack the constraints of its yin half.
The advantage to this is it makes Naruto uber powerful, and if anyone were ever to take the fox out of him, there plan would not bear fruit because of the imbalance. Itachi mentions that the fox must be captured last because it is so powerful that the king of hell statue would fall apart without the other eight tails in it. The same would happen if only the yang were to be locked inside because of its power and pure evil, it would crumble the statue doing god knows what. So it would give Naruto a nearly unlimited supply of chakra when channeled and yet if anyone were to take it, it would have a fail-safe.
In second effect, the jutsu Jiraya refers to, could be the death god once again. Yet this time the death god would take the other half of the fox instead of Naruto’s soul. Minato might have foreseen that it was indeed Madara and if he indeed were behind the summoning, he would be incredibly powerful and possibly even immortal, thus leaving death god as the only way of truly stopping Madara. And yet the seal could force the death god to take the fox instead of the summoner’s soul. Thus ridding the world of both Madara, or whoever was powerful enough to summon the fox and the rest of the fox at the same time. Thus with the sacrifice of his life, Minato could rid the world of both the fox, and this super powerful villain at some point.
A second point goes directly into the control of the fox. I believe at some point kishi will try to connect the fourth and Itachi together in the plot to get rid of Madara or whomever summoned the fox. Not directly together though, but a last order Minato left to the elders (mostly Danzo). The fourth is a very nice and decent person to those close enough to him, but if you were not on his side he was efficiently ruthless and cold hearted. Notice that his fighting style is quick and direct, he wants it over as soon as possible. With the lone ninja from the stone for example, and the others (in that entire platoon of fifty ninja, how many do you think he left alive, or in the squad that came to kill Kakashi and rin?).
Though not a man Danzo would be too proud of, Minato was incredibly cold hearted and ruthlessly efficient with those who opposed the leaf, a style that Danzo would hold as a prime example of what the leaf should be, compared to that of the third. Minato arrived to the scene late, probably because he was going over last minute plans with the elders in a top-secret meeting. In which he discussed that only an Uchiha can control the fox, and thus that one must be found and entrusted to help Naruto with the fox.
The elders agreed to find one (yet they probably went to the extreme when they found their trusty uchiha). Itachi was found because he was willing to kill his entire family for the village’s sake. This would be there agent to help Naruto control the fox. As a note, the fourth had no idea as to whom they would pick (itachi was only like 5 years old), or how but he did tell them that an uchiha must be found. On another tangent, this would be the threat that itachi held against the leaf. Not only would he come back to the leaf if they harmed saskue, but also he would release the rest of the fox and destroy the entire village. This is something the elders would fear, not only was itachi probably the third or fourth strongest the village had ever produced, but he would have the fox which no one would be able to fight.
And thus Danzo could not harm saskue and finish the Uchiha, and he could not kill Naruto because he was the one person who could eventually rise up and stop madara. This would explain Itachi’s warning that he would hope that Naruto would never need the help of the power because that would mean that madara has finally attacked the leaf and that the only way is to release the violent and nearly uncontrollable side of the fox, which is last minute because even if you were to stop Madara, the fox could get loose and finish the job anyway.
That’s it for theories on background stuff, lets get to some future predictions. 1) Kakashi gets stopped by his father on his walk of death and told to return and be the hero his friends and master were. He loses the sharingan as it finally burns out but in the process gives all the chakra it had taken from Kakashi throughout the years, giving the new white fang a new source of energy versus pein (it returns to a normal eye state, never again going sharingan). Kakashi gets newfound power and all the amazing techniques he has seen but took too much chakra, he can now use and begins to attack pein with increasing power.
2) Tsunade has to die, and if not versus pein, then it will be versus Danzo who commits a coup against Tsunade in her weakened state. This would be supported by the other two elders, and thus no one can contend Danzo as the new hokage. Though this would be short lived because Saskue would soon attack, and with the help of Naruto and Sakura would kill (most likely beat the crap out of and leave alive) the elders in order to regain power and avenge their fallen persons.
They’d have a little get together, but Saskue would leave because he is a douche, jk, he’d leave because he would say that he still has one more man to go after before he can rest in peace about his vengeance on those who betrayed the uchiha. Sakura would want to fight but Naruto would stop her telling her that there’s no time to fight and they need to rebuild Konoha before they can meet Saskue again. As they say goodbye, Saskue looks into Naruto’s eyes because he is now more curious about the fox and in front of the gate he sees a key.
He asks the frog what he’s there for, and the frog hypnotized, says he the key to open up the gate. Saskue reaches for the key, only to find Itachi’s hand grab his own saying “now is not the time, but soon I’ll reveal everything to you my little brother”, Saskue is then forced out by itachi back to the outside.
They part ways once again, yet this time with a better feeling then the last two times. On the way out saskue runs into Kakashi, they briefly exchange some facts, one Saskue notices first that kakashi is no longer wearing a mask, and second that his left eye is no longer a sharingan. Kakashi then briefly mentions to be careful with Madara, as he fought the first and has survived all these years. Saskue is surprised he knows, but kakashi says be careful because something isn’t quite right with madara (hints at that he suspects Madara to be obito in some form). Saskue, then asks one last question, “How strong has he become?”… Kakashi answers that he has surpassed any other living ninja currently in konoha and is right behind saskue, and catching up fast, just like last time, which Kakashi chuckles at the irony. Saskue smiles and disappears with the rest of hawk.
Later Karin asks if they should have killed naruto then because he might be able to stop Saskue, Saskue says no, that Naruto will be of more help to him in the end then anyone else can foresee at the moment. Kakashi becomes the sixth hokage, but hands it off to Naruto officially, but volunteers to act as hokage so he can go out and fight Madara and pein, who is still alive because Nagato is still alive.
3) BONUS!!!: Kakashi is on the verge of death after the pein fight (he did come back to life, but he kept the sharingan unlike my previous prediction). Sakura is crying over kakashi and also for the loss of tsunade. Kakashi says not to worry, take his sharingan (sakura has lost one of her eyes at this point). Sakura doesn’t want too, but kakashi tells her he won’t need it where he’s going, not to mention that is can still be used for good to help konoha. With this sakura gains the sharingan, and all that it has seen (a great way of caring info that a dying kakashi has no time to explain), along with sakura’s more chakra, she can use it w/out wearing out as quick. Kakashi’s last words are to protect Naruto, get saskue back, and protect the village in the way kakashi never was able too.
Now that was short-range predictions, the next few will be for future arcs.
1) Kabuto will at some point help the leaf because he has always been back in forth with what he wants to do. He also highly respects Naruto and will no doubt help him defeat Akatsuki in some way. But he will return as a villain near the end of the series, probably the last one too as to show the changing of the generation as Jiraya, Tsunade, Madara, and oro have all been killed.
2) Kisame is undoubtedly a curious character. My belief is that he will not change sides so quickly. He is not as sharp as itachi or madara and even though he seems to have had problems with madara in the past, he is very well content with causing as much chaos and destruction as possible. Notice how he is a shark, and thus enjoys being the predator rather than the prey. He is also very confusing in that he had a great relationship with itachi, even considering him superior in all aspects.
This may because the sharingan can control monsters (kisame), or because he was in for the plan of eventually stopping madara (who itachi and kisame could not take on there own especially with pein as madara’s bitch). So kisame could be fitting to make the world more stable or he will join whatever side has the funest fight (much like Kenpachi, ironically, like kenpachi does not know the name of his sword, Kisame may only be able to use one element, which isn’t a problem with his strength).
Whichever way kisame goes (and not in that meaning), he is a crapshoot with anyone’s guess as good as another’s. A prime example of a random shot in the dark.
3)Pein will stay against Naruto because as long as there are multiple villages, there will be war. He might go against madara though because he did “cry” when tobi/madara said “the true power of the sharingan”. But he will definitely remain against Naruto, probably being the most dangerous enemy after saskue knocks off madara. At some point.
Info: I’m not even going to go and try with the Raikage and that shit, that is just so open ended I’ll just sit back and hopefully get to enjoy whatever kishi decides to do with it.