You know, I do wonder if Naruto will share this info to Sakura/Obito. They know the later half of the beginning in which people used chakra for battles and force to bring peace. This is why Naruto thought he created ninjutsu, rather than ninshuu. Sakura wouldn't ask that, but ask the serious portion, so in this case, Naruto would ask from the beginning. That said I do wonder though. He doesn't have to say every details, but I could see him talking about peace and balance.
This is Naruto we are talking about, he'll say something 'I made a promise to an old man, I will stop this cycle of hatred' or something vague like he did when he leant the Bijuus names, or his father within the seal.
Well, I do wonder why Madara did obtain the eyes in the first place. I really think we have to wait for more chapters to get all answers. It almost feel like Madara is Indra since he was able to gain the eyes. That or maybe Indra is in all of them, especially the cursed mind of Uchiha. I guess Naruto's kind went extinct so now, Naruto is the only one left. Hm...
Madara got the Rinnigan because he infused Senju's chakra within him and was close to death, (we'll get a better idea whenever we get the Madara flashback, because we WILL get a flashback). I think Madara was Indra, not is, I posted this before, I believe that Hashirima and Madara were the previous incarnation of the brothers, and once they died were reborn as Naruto and Sasuke, Sasuke was born short after Madara died so it actuall makes sense and who knows maybe the soul of Ashura chose to be reborn only if his older was reborn, that's why he's a few months older, also he chose Naruto as no Senjus were being born, and chose the closest relation instead, and maybe that is the key to breaking the cycle of hatred, the fued not being between Senju and Uchiha, so neither is bound by history.
It's true that 兄弟 is neutral, but it's more than likely speaking about a pair of brothers. Reading it, I would think a set of brothers.
Although it's also really interesting that Kishimoto does make details about Hagoromo's sibling a bit vague...I think it's more possible for the sibling to be a guy.
*reread it and I thought it was obvious that he has a brother?
I originally thought it was sister, and reread it and saw brother, though Mangastream does say Siblings not brother, They do have long hair, (but then again so does Madara and Hashirama) My original thought was that the other sibling went onto create the Uzumaki Clan, they decided not to get between the fueds between their nephews and chose a more spiritual path away from civilisation, and work on defensive Fuin Jutsu's instead or maybe they chose to be the guardians of the Ten Tails body....Actually just had a thought, what if that was why they were destroyed, Madara read the history on the tombs, found out the Uzumaki's protecting the seal that held the ten tails body and used the war to get the Clan destroyed and gain control of the body. We have no idea how Madara managed to get the Ten tails did he simply summon it? Also why did he choose a Uzumaki to implant his eyes into? I wouldn't be surprised at all if there is more to the Uzumaki than being distantly related to the Senju...though if that is the case it will mean we'll have to wait till Madara's flashback to find out.
Either way it certainly sounds like it will make for an interest fanfic.