Board Thread:Naruto Discussions/@comment-26479810-20171222153110/@comment-734582-20171222180623

Vladosaurus wrote: Third of all, there is no possible way for Naruto to have lost these chakras. There is. The biju were still in Chibaku Tensei when he undid IT. So it would have taken no more effort than Sasuke absorbing a tiny bit of their chakra, then working with Naruto to undo the IT. After all, Sasuke would only be missing Yin Kurama's chakra (which naruto had).

It's not clear if undoing IT really requires Biju chakra to be spent, or merely requires that it is present. In the second case, Naruto having once possessed Biju chakra may already be enough, similar to how Gaara retained his Shukaku-given powers despite not having shukaku, or how Nagato was revived with Rinnegan despite them not being his natural eyes. There's evidence that after a while, possessing a power counts as your "own". Gaara was able to pull out Shukaku despite him still retaining some of that chakra being impossible, so clearly a biju influences it's host in a way that remains even after biju extraction.

The third alternative is that if Biju chakra merely needs to be present, then Sasuke's CB's still contain Biju chakra and so he meets the conditions for all of it sans Yin Kurama.

Whatever path is chosen, there are explanations that don't require Naruto to still have the Biju. And there isn't enough evidence to confidently have a say in what exactly was the final cause of the IT dispelling. Golden TFGVNXP wrote: After he received the yang Six Paths chakras, he had SPSM and had all 9 tailed beasts chakras He was given a bit of each Biju's chakra, yes. He did not possess actual Biju other than Yin Kurama, and in the Boruto era he possesses the fully restored Kurama. Note that the series is not very consistent or precise with the terminology here. However, from the context it is clear that Naruto received Biju chakra without their actual "spirit" (e.g. what makes a Biju a Biju, and not just a chakra mass). Else, he would've been able to talk to the Biju inside him from the start.

It's not clear what the Biju inside Naruto were exactly, but we've seen with Minato and Kushina that chakra can take the form of a chakra ghost, which exhibits all the memories, abilities and personality traits of the original. So, it's likely that Hagoromo simply allowed these to come out.