YO! I'm gonna take a huge shot in the dark on this one but I think zetsu/sandshrew might be the akatsuki mastermind. Zetsu so far has done nothing but hide around and watch fights and dispose of dead ninja right? What if while madara and the first hokage were fighting at the valley of the end zetsu happened to be present at that fight. The fight was concluded and after the first left, madara made some deal with zetsu to use his technique to recycle(i dunno his soul or somethin) madara to another corpse(obito....sorry). Then Madara assembles akatsuki. I think Pain might be a compilation of fallen recycled ninja that zetsu reanimated with a technique. Jiriya did say he fought all of pain's bodies before. maybe one of them had rin'nengan. huh? whaddya think? too farfetched? it came to me randomly so i started typing. i need food.....