Board Thread:Naruto Discussions/@comment-25139119-20140704145132/@comment-24938412-20140705080600

I see the Indra/Ashura reincarnations as descending wills. That is, even after their deaths, their wills simply passed on through their respective descendants, dormant most of the time except for special instances when they would resurface together. Hagoromo said there were many Indras and Ashuras throughout history, but then Madara unexpectedly deviated from the formula by combining his and Hashirama's power, thus gaining the Sage's own power. (ultimately orchestrated by Black Zetsu who corrupted the tablet) So, this might have something to do with Sasuke also possessing Indra's chakra/will/energy/ehatever at the same time. Maybe, maybe not.

Also, am I the only one who doesn't think the “reincarnation" is literal? I always considered it to concern only their will being reborn, in a kind of metaphysical sense, rather than the actual souls of Indra and Ashura being reborn into new bodies.