The Sage's Sons...
Why?
1) They started the war between the Uchiha and the Senju...so they'd be the only ones of course to know some solution or something like that...
2) They're the only ones that make sense right now...it can't be the Sage because he's just one person...it's the "ONE'S" who know everything. The sage died and his two sons carried on his lineage...the older son was the one to betray the younger.
How is this even plausible?
1) The scroll Suigetsu found was owned by the 2nd person to ever develop Edo Tensei. Sureeee Kabuto was able to modify the technique, but Orochimaru still knows something that Kabuto doesn't know about it...and that leads to...#2
2) The Journey Sasuke and Orochimaru may have gone on was to maybe...find the bodies and the maybe the equipment needed to Edo Tensei them...or revive with whatever jutsu is on that miracle scroll.
Why did I choose the two brothers and why do I think they'll help decide the end of this war...?
1) The Juubi isn't going to be defeated by just the Ninja alliance and Naruto...no way....there has to be some outside force...
2) Just look at Naruto Chapter 612....18 pages of ninjas making concrete...that the Juubi just shakes off when they're done.
3) They're probably the only ones on par with Madara and Hashirama...
4) They've inherited the wisdom of the Sage...

What other crazy predictions do I have...?
1) Some way...some how...the Sage is going to end up showing up if Naruto is the one to defeat Madara, Obito, and the Juubi...(maybe even Sasuke...), I don't know how but...I just have a strange feeling he's going to show up the same way Minato and Kushina appeared when Naruto was on the brink of surrender to Kurama.
2) Orochimaru is never going to die. That's just it...he's spread his body into so many forms....so many people....he may just end up being the future villain for whoever surpasses Naruto's generation...maybe Naruto's kids...
2.1) I mean just look at what happened after Itachi supposedly sucked up Orochimaru in that Susano'O vial...there was that white snake that left Sasuke...that alone could of carried Orochimaru's essence and he could of easily been revived somehow...
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If you have any ideas, feel free to share.