Board Thread:Theories and Speculation/@comment-1783334-20150507053750/@comment-2043993-20150507180424

it might be Kabuto under the hood, reason: he's an old enemy, he's capable of going up against very powerful shinobi, he experiments and have a large amount of intel on nearly everyone thus making it likely that he would have found Obito's collection and transplanted some eyes to various people, he also had a white zetsu to play with thus making it likely that the boyn with the sharingan is a product of those experiments, plus his whereabouts are presently unknown after the war.

reasons against: he's apparently turned a new leaf and become sort of good, helping Sasuke and not wanting to base his life on something or somebody else ever again.