Board Thread:Naruto Discussions/@comment-1512913-20170417105433/@comment-25122992-20170417113154

Well, not sure about Izuna retaining an EMS part of his own eyes after their possession by Madara, but as for me, Izuna wouldn't be able to handle these eyes as Rinnegan as masterfully as Madara if they were to return to him. My point is that technically it was Madara who developed these eyes into Rinnegan, not Izuna, thus he is the original owner of the newly-awakened Rinnegan, not Izuna. This developement wouldn't even be possible without Madara taking part in it since he's the inheritor of Indra's chakra, one of the necessary components for the Rinnegan to emerge. As such, I mean that Izuna's eyes with Madara as an owner went far beyond the level they could've reach had they stayed by Izuna all along, and because this power wouldn't be natural for Izuna himself, he would never reach the same skill in wielding them as the Rinnegan, though he'd still be able to use them like Nagato or Obito did.