I wonder if who BZ is really matters.. But did anyone last chapter notice how BZ changed voices or something like that, right before Sasuke asked who he was? And also at some points he sounds like he's talking for more than one person, saying 'we must' and 'our mother'. I also think that it isn't coincidence how half of BZ was on Naruto and the other half on Sasuke's other side. This also makes me think that when Sasuke noticed the voice change, it was because half of BZ was talking differently then the other half(maybe). I wonder further, is BZ really just Hamura? Did Kaguya really 'create' BZ with just chakra? I don't think so. It makes sense that she could use the yin yang power to create her sons, it balances out and all. But I don't think she is as Godly as she seems. In these scenarios the strongest thing alive is considered a 'god', just because no one else has reached that higher level. I think Kaguya has access to the source of chakra, but she did not actually create it(just like how BZ didn't actually create the story of Shinobi). So, again, it would make sense that even Kaguya might be limited because chakra has it's own properties to balance out(yin yang, there's more too). So what if the two opposing forces, that are attracted to each other but remain divided somehow merge? I think this is how BZ came about. It really just seems to balance out perfectly. You have the two 'good' sons, and the 'evil' (merged?)son.
Now the question would be how did that happen; what could cause this break in balance? I think that somehow when Hagoromo and Hamura sealed Kaguya the fulcrum of balance vanished and forcefully created a negative(opposite but same) reality(like tsukiyomi) to bring back balance. I believe that this explains why he is 'black' zetsu, and possibly where he originally came from and maybe even where Kaguya was sealed. You could say they switched places, and have been trying to come back together this whole time. Sound familiar? Yin yang again, Hagoromo and Hamura, Kaguya and BZ, Indra and Ashura, Uchiha and Senju, Naruto and Sasuke, Heaven and Earth, Reality and Dream. But anyways, Hagoromo even mentioned that if an individual possesses too much power it just doesn't end up right. When they sealed her I believe their negative(opposite) energy was transferred to the another reality merged(since that would be opposite). But it wasn't simply combined, more like BZ just contains the 'evil halves' of both of them. So the difference between Kaguya/BZ and Naruto/Sasuke is that you have 2 pure 'evil's vs 2 opposing 'good's.
"Two opposing things can create all things when working together"
Somehow Naruto and Sasuke have the advantage because they are actually using the balance of chakra to their advantage, instead of just having straight shit loads of chakra like Kaguya right now. I think they even hint at this in the new chapter bc Kaguya has all the chakra, but she doesn't know the extent of justu and how they work. She uses a more direct approach like shifting dimension at once, but Justus are actually the fine tuning of chakra. Naruto and Sasuke will work together and their strength will multiply, while Kaguya's strength is finite and only increasing from what she takes. That's prolly why Kaguya separated them, she could already tell that they would be huge trouble together. You can say it's just coz she didn't want to get sealed, but before she saw their feats I'm pretty sure she didn't ever consider it. I really feel like it makes some sense, and might lead to some more answers later on. But idk fosho until we find out first hand!
