Board Thread:Naruto Discussions/@comment-1512913-20170417105433/@comment-734582-20170417171618

Elveonora wrote: So you think that Izuna and Itachi would't be able to use the Rinnegan as well as Madara and Sasuke respectively, but still better than anyone else would? Basically, yes. After all the Rinnegan part isn't their own power. Even without the Rinnegan, Madara would still have Six Paths chakra and a considerable amount of power, exactly as we saw him have as an Edo Tensei and as an eyeless Rinne tensei.

Still, the eye that transformed is their eye, and their chakra is compatible which is what made the EMS a thing in the first place. So while they aren't quite a true owner, they nevertheless would be able to use the eye on a high level. Compare this to say Nagato who had no compatibility with either EMS or Rinnegan and so needed years before he could access it's power properly. Obito could access more power from the start since he had Uchiha blood and Hashirama's cells (he had much less time than Nagato to learn it though). Extrapolating, the relatives of Rinnegan users would be significantly better at using these eyes, and those who can share eyes would be one step below True Owners.

Elveonora wrote: For the EMS, I wonder if the design would change. Sasuke's EMS looks like his MS with Itachi's put in. So if Itachi were to take back his eyes, would the design remain or would it look more like his own with less resemblance to Sasuke's? Or would Itachi need to take Sasuke's original eyes for different design? Really mysterious and interesting stuff. I think it makes sense that that whatever chakra gets overpowered, is what takes on the lesser form. IE Itachi's eye produces chakra since it's actual flesh, but Sasuke's body contains far more cells and thus his chakra would overpower Itachi's. So, the EMS is Sasuke's power (the eye power got overwritten to become Amaterasu/Kagutsuchi and not Tsukuyome/Amaterasu) with Itachi's power subservient. The EMS design is Sasuke's design with Itachi's as a detail.

The thing i do wonder is whether this effect is reversed, and i think two answers exist. If the eye is returned quickly then the EMS would reverse, as whatever chakra Sasuke put into this would quickly fade and so Itachi would have his regular eye again. The other answer is that it seems that if the eye exists as EMS long enough, it would be imprinted with Sasuke's chakra and so the EMS status would be maintained. We saw that Obito was able to Pseudo-Edo tensei himself to Kakashi, and Kakashi had his eye for years and so Obito's chakra left an imprint. Gaara was Shukaku's jinchuriki for years and so his chakra left an imprint, allowing him to extract Shukaku despite not being jinchuriki for months (and so whatever chakra he possessed as a Jinchuriki was refreshed). Despite being transplants, Nagato was Edo Tensei'd with Rinnegan, so the rinnegan's chakra left an imprint in Nagato.

This leaves me with the final question, namely what will it look like. I honestly don't know. The imprint argument suggests the eye stays the same. The Subservience argument suggests the shape would invert. I cannot think of any proof or evidence or even a hint about something that connects these two arguments, something that hints about which one would be stronger.