Board Thread:Theories and Speculation/@comment-26403664-20160206050741/@comment-26773508-20160206070959

Your Indra's MS theory seems plausible. The sharingan is a dojutsu that is enhanced by hatred. It wouldn't come as a surprise if Indra unlocked the MS due to the grief and hatred that resulted after Hagoromo's death. Or maybe he already had the MS and could use normal Susanoo, while the extreme hatred that resulted from Hagoromo's choices enhanced his MS even further, which resulted in Indra unlocking his Perfect Susanoo.

However, I think it's more likely that Indra had Perfect Susanoo before Hagoromo made his fateful choice. The reason being that Indra had access to part of his father's Six Paths Chakra, which would have naturally enhanced his Susanoo even though he likely did not have EMS. DMS Kakashi is the only example of this phenomenon, since he was able to unlock a flying Perfect Susanoo without possessing EMS. The only thing that could have unlocked PS in DMS Kakashi/Obito is Rikudo Chakra.

Indra's transmigrants, however, did not possess the original body of Indra. Not only that, their bloodlines had diluted away from the original Ootsutsuki bloodline considerably by the time Madara was born. And so even though Madara and Sasgay are transmigrants, it seems that Indra's chakra clung to their bodies in a more-or-less diluted form, which is probably why they needed to awaken the EMS to access some of Indra's true power.

I have no opinion on Ashura's chakra mode. I don't think it looks like the silhouette of the Juubi that was first shown when Tobi explained his plans in the Five Kage Summit. Rather, it resembles Kurama mode way too much for comfort. So I think Ashura had something to do with Kurama.