Rikudo Sennin update
sorry guys if you see your theory here, i just took them and sew them into something coherent to try and at least make sense of the many ideas we get from the recent development.
there's this theory i read awhile ago bout the RS being an Uzumaki... i gave it some thought and it does make sense.
The uzumaki were known for their seals, but there was no mention that they were pros in ninjutsu for some reason. There was also a mention that they were quite crude in making seals. They were also mentioned as distant cousins of the senju.
First, there is a missing piece that we need to supply for this theory. Where did the rinnegan originate? as of now, there are 2 mainstream theories i picked up from you guys.
1. It was unique to the Rikudo Sage, and it only pops out in times of great strife.
2. It was part of the juubi's sharinnegan.
if we pick up on theory 1, then it could be backed up by Nagato being an Uzumaki. The rinnegan could has a genetic affinity to the RS' clan, the Uzumaki. i'm not sure how to move forward with this one.
if we pick up on theory 2, then the RS must have some unique abilities to even face the juubi. like a unique ability to sense chakra (since nobody prior him could), and the ability to at least seal the juubi partially within him to at least gain some of it's chakra to further reinforce the seal (will be discussed later.)
i'd go with theory 2 to have more discussion.
If we go with theory 2, The Uzumaki lineage could explain how RS was able to face the juubi; With Seals. It was mentioned that the uzumaki could make potent seals, though crude, which lead me to believe that these crude seals could be what the RS used to seal the juubi within him. These are the artifacts that we see in the RS silhouette's such as the jewel, the horns, the priest staff, and maybe tattoos that look like what we see in naruto's RS mode.
and when he finally gained partial control of the juubi, similar to how naruto's seal leaks chakra that blends with his own. He was able to muster a powerful enough seal to "reinforce" his physical seals, thus the chakra form of the seals as we have seen on naruto.
therefore, the sealing tech used on naruto could be exactly the seal that RS used to take the juubi's chakra.
now, where would the senju, uchiha, other clans go from here?
since the RS was already a jink prior to having sons and he was quite gifted for being the first guy to be sense and manipulate chakra, I think the special abilities such as dojutsu, powerful bodies, and affinity to ninjutsu were manifestations of the juubi's power and the unique genetic traits that originated from RS' lineage. thus his descendants were naturally proficient ninjutsu users, while the other uzumakis who weren't offshoot from RS weren't. (nagato aside since he had the rinnegan).
let's discuss. i know it got holes and stuff but im not sure how to connect the dots anymore. help me out if you can.