Re: Naruto 441 predictions/spoiler discussions
I think Rikudou will be neutral instead. Orochimaru combined with Kabuto appear to being set up as the final villain for the series with Kabuto emphasising his will to fight both Sasuke and then Naruto. I can see the series ending with him fighting both of them. Madara may very well be the ultimate villain as well, but I prefer the use of Kabuto as it has nice mirroring of the manga's beginning.
I think Rikudou will be neutral because he's got no real reason with that power to favour either side. Until we learn more about him all he seems to have done is allowed for the creation of the ninja system that Pain and even Minato see the flaws in. But the question is what was before that, and whether it was any better. Also, I'd say the only other neutral character would have the Killer Bee right now so it wouldn't hurt to have someone else with insane strength but who doesn't care.
Ultimately though if Rikudou does appear I can't see it being for very long.