It is a difficult one
As I can see quite a few members, [despite making valid points], are just rejecting the notion completely, that the sage may have more to do with the Uzumaki than let on.
Refraining from joining in, I'm now tempted to do so:
1. The sage had two sons as we know from the Manga -
A. One eventually had descendent as known as the Uchiha
B. One eventually had descendent known as the Senju
It was stated that the Uzumaki were ''Distant Blood Relatives'' of the Senju.
Now, the most simple and logical answer would be the Uzumaki are a branch off, descendant of the Younger Son.
However this was never stated, it was just mentioned, [by Kushina an Uzumaki], that they were distant blood relatives of the Senju
The opinion that they are descendants has never been stated, [I am not saying the Sage is an Uzumaki keep reading]
Now Kushina being an Uzumaki, would know that they are related, what she wouldn't know is if the Uzumaki were distant blood relatives of the Uchiha , [I know but trust me keep reading]
The fact that it wasn't mentioned makes it a possibility, BUUUUUUUUUUT, we work with what the manga has informed us, and since it has not been mentioned we cannot say this.
This goes for the Sage being an Uzumaki
Although i am a big fan and propagator of the Sage being or at least having a major part with the Uzumaki, we cannot state this until it states so in the manga
It has also been mentioned that the Sage was of the name Ōtsutsuki Hagoromo
so we know that he had his own clan name.
My point in all of this, is that Kishi, just as with Obito, left many questions that 75% of people refused to address to its simplicity or absurdity, which does need answering:
1. Why would a branch off clan produce the ''promised child'' [so to speak], as the ''Sage's Return'', [so to speak], and not one of the Uchiha or Senju, as they are the most clear direct descendants
2. Why would Madara select an Uzumaki child to leave his eyes too in his death?
3. The Tailed beast sealing Jutsu originates from the sage we can agree as he was the first Jinchuuriki, however why has the Uchiha nor Senju been mentioned to have anything of this, whereas the Uzumaki were known for this, and considering they provided consistent hosts for Kurama that their sealing included Tailed beast seals, as Kushina taught Minato the 4 signed seal used on Naruto.
4. Why were they feared to the point they were destroyed?, very convenient, as there is no one who seems to know their full history
Now note, although I am a propagator of the Sage being a major part of the Uzumaki, nothing is confirmed so nothing can be stated as fact, however the fact that many reject the above questions as nothing but irrelevant are clearly avoiding a massive foreshadow, I mean the main character is an Uzumaki that alone should scream something at everybody
