Board Thread:Theories and Speculation/@comment-26889573-20151008053113/@comment-1872728-20151015134110

And all that above, this is the reason why I think there are only three animal Sage Modes.

Hashirama's one is different though, which I also have a theory on. But don't worry, this one is not as confusing as the ones above.

Since this thread is about Sage Modes, then I guess I'm not going off topic. My theory is that Hashirama's Sage Mode is the diluted Sage Mode of Hagoromo, similar to how the Sharingan is the diluted eye of Hagoromo (Rinnegan). Then based on that, if Indra also had the Sharingan, then it would mean that Asura also had that Sage Mode. Also, the eye on Hagoromo's forehead? I think it's the Sage Mode mark. Which also explains why Hashirama's Sage Mode also has something that looks like an eye. Opinions?