as of right now there is no prof that the sage is or isnt a uzumaki (unless i messed)
most of people r saying that sage was a uzumaki and i agree somewhat if he was a uzumaki he had to to had very special chakra to surpass the 10 tail chakra (just like kushina said that she had the chakra to surpass the 9 tail chakra)
but the sage had to go through hard traning to do all that (to become a jinchuuriki) but he should have got help from the uzumaki clan the seal the 10tail and by doing that the uzumaki clan lost their strongest member(died) so after that he went around the naruto world for peace/something along with that like jiraiya did but different and when he was diying he created the 9 tails and he give his power to his son(cut his power in half so both well have the power but only half of it) and if u all the sage power (weak version sage full power) then u need the eyes and body to have it (dna)
most of people r saying that sage was a uzumaki and i agree somewhat if he was a uzumaki he had to to had very special chakra to surpass the 10 tail chakra (just like kushina said that she had the chakra to surpass the 9 tail chakra)
but the sage had to go through hard traning to do all that (to become a jinchuuriki) but he should have got help from the uzumaki clan the seal the 10tail and by doing that the uzumaki clan lost their strongest member(died) so after that he went around the naruto world for peace/something along with that like jiraiya did but different and when he was diying he created the 9 tails and he give his power to his son(cut his power in half so both well have the power but only half of it) and if u all the sage power (weak version sage full power) then u need the eyes and body to have it (dna)