I know there are several theories out there about the merging of Kurama mode and sage mode. I haven't seen one that matches my version of the theory, if there is please point it out.
Theory:
When Kurama is trying to gather up chakra, it always shows him in a meditation pose like Naruto is in when he is gathering nature energy. Therefore I believe that Kurama's chakra is nature chakra. However, while Naruto is in KM he can't hurt Juubito, I believe this is because there isn't a proper balance for it to be on the same level as senjutsu.
While Naruto was training to perfect sage mode, the toads tried to merge with Naruto so he had a steady supply of nature energy, but they couldn't because of Kurama's chakra. I believe this is because Kurama is incomplete inside of Naruto. Naruto has the yang Kurama and Minato has the Yin Kurama (or vice-versa). Without the proper balance, he can't give Naruto the full nature energy.
With the revelation that the Edo's are basically mortal and the showing of Kurama's other half. I believe that Minato will transfer the Yin Kurama to Naruto before he gets killed, which will put Kurama into perfect balance. Kurama will then be able to continuously collect Nature energy in perfect balance, and transfer it to Naruto, so that he can stay in Sage mode indefinitely.
Theory:
When Kurama is trying to gather up chakra, it always shows him in a meditation pose like Naruto is in when he is gathering nature energy. Therefore I believe that Kurama's chakra is nature chakra. However, while Naruto is in KM he can't hurt Juubito, I believe this is because there isn't a proper balance for it to be on the same level as senjutsu.
While Naruto was training to perfect sage mode, the toads tried to merge with Naruto so he had a steady supply of nature energy, but they couldn't because of Kurama's chakra. I believe this is because Kurama is incomplete inside of Naruto. Naruto has the yang Kurama and Minato has the Yin Kurama (or vice-versa). Without the proper balance, he can't give Naruto the full nature energy.
With the revelation that the Edo's are basically mortal and the showing of Kurama's other half. I believe that Minato will transfer the Yin Kurama to Naruto before he gets killed, which will put Kurama into perfect balance. Kurama will then be able to continuously collect Nature energy in perfect balance, and transfer it to Naruto, so that he can stay in Sage mode indefinitely.

