just wondering why is naruto fox mode also rinkodu mode is that naruto have been rinkodu from birth only that he didnt know because so far naruto is the closest person we have seen to the sage of 6 path[i mean physical appearance]. Not even madara who claims to be rinkodu is shown that way. my question is, is naruto rinkodu due to the fox or due to the way he was born
My answer is unlikely to be satisfying as I don't fully know. However, I think his appearance has to do both with his Uzumaki lineage, the Kyuubi's chakra, and the new seal (replacing eight-trigrams) recognized by the Kyuubi as one of the So6P's, so I refer to it as the So6P seal (As evidenced on Naruto's body). I think that when he taps into these resources he has a strong resonance not previously witnessed (There've been only 2 previous Kyuubi Jinchuuriki), which leads to such a radical change in appearance.
If Bee were to do the same thing and use the Hachibi's chakra, he would look like himself but with a red chakra cloak and however many tails he wanted, up to 8. Now Naruto could do this before, but that was with the eight-trigrams seal and not the new So6P's seal he presently uses and now changes appearance radically. That's proof that the new seal is involved. The other thing that changed at the same time as the seal, so it presents a confound as to what is doing what, is that Naruto stole the Kyuubi's chakra alone (sans the will and hatred) and sealed/stored a pure Kyuubi chakra. I don't recall, but I think his chakra changed before closing the seal, so I'm certain that this form of the Kyuubi's chakra is part of the transformation.
The Uzumaki are distant blood relatives to the Senju; thus they share genetics going back to the younger son and the So6P himself. Naturally, Naruto would have his genes set at conception. Further, story wise, Naruto is meant to represent or be the reincarnation of the younger song/the sage's body, while Sasuke is meant to be the same for the elder son/sage's eyes.
However, the Kyuubi chakra and seals weren't guaranteed until about 1-2 (guessing here) hours after birth. This was naturally when Minato performed the DRS to seal the Yin Kyuubi chakra and himself in the Shinigami, while Naruto had the Yang Kyuubi and some of Minato's and Kushina's chakra sealed in him with eight-trigrams (which has been replaced with the So6P seal).
All three of these things make him the closest in appearance to the younger son of the So6P's (Madara is likely to only be close with the Juubi, despite possessing Hashirama's DNA he's still a shell of his former self, which was Uchiha). Naruto is meant (meant as in the story is being written this way by Kishimoto) to be the reincarnation of the So6P younger son who had the body, willpower, and physical energy. This sounds a lot like Naruto no?
No, Naruto is not the Rikodou Sennin himself (That requires both the eyes and body, this is what Madara is definitely after and Kabuto may be after) or his reincarnation based on the evidence so far. Rather it suggests that he is the reincarnation of the son/So6P's body. Naruto would need a Rinnegan, and he has no use for it. He's already 17? He's not mastered plenty of his own stuff, so don't count on that.