I was going to suggest that while all the others summonings are done with any body that Kabuto could "stock" and the dead were bind to a random body, (and so they look exactly when they died), Edo Mandara has his own body back, at least it's the idea i got, and it was enhanced/restored using HC cells to the point that he has the face in the chest.
So again, HC could prove to be another "counter" to any type of situation, but i do refute my own "idea" due to fact that the appearance of every edo tensei summoning has result in the person having the same one of when they died, why would Mandara be diferente even with HC ? It seems that what counts is the souls "age" not the body.
So i got to think in another direction, Mandara said that he awoke is rinnegan near his death ? Couldn't he have died in the process of awakening the eyes ? or very short time after, or even, due to some illness (like itachi), or any other factor ? that would mean that he didnt die of old age, that could explain the more youthful appearance of his soul/self.
Just another theory before today's chapter :)
I think the most popular theory regarding Madara's death is that it was Rinnegan-related. However, I believe he likely lived for quite some time after his battle with Hashirama, and maintained his youthful appearance in part because of the Hashirama Cells he'd already obtained (which also probably helped him awaken his Rinnegan). Madara at least survived long enough to know about Nagato, unless Madara has been revived more than once. If Tobi is Izuna, and possessed the Rinnegan at some point, it's possible. Maybe Madara/Izuna traded off the Rinnegan/revivals a few times before deciding to let Madara stay dead until their plans are closer to complete, with Nagato being given the Rinnegan to hold on to the eyes for a few decades while Tobi prepared. Nagato, being an Uzumaki, is better able to handle the life force-related cost of using the Rinnegan.
Originally Posted by Majere
assuming that there is a "life force related" cost of using the rinnegan. nagato seemed to be in perfect health until he used the jutsu that merged the statue to him and from the single real picture of the SO6P he seemed to be at ok health and he looked like he was around the age of jiraiya. in a lot of ways it would make sense if the reason why the SO6P could get so old(50-60ish) was due to him being an uzumaki, just like nagato due to their longivity and stamina if rinnegan has a life force related cost.
IT's OUT!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!
Congratulation to all those who defended their bet on Tobi being Obito because it certainly looks like it now