So this theory was going on in my mind for a while now. And finally today I feel like sharing it with you guys.
What if SO6P was from Uzumaki Clan? Yeah it may not sound appealing but let me explain some more.
Uzumaki Clan have been known for their strong sealing jutsu. They have strong life force and chakra. And with those sealing jutsu and strong life force, SO6P was able to defeat/seal the ten tails. He then got a new power,the power of eye. Yeah I think he got the visual power from the ten tails.
I do know senju and uchiha were formed after he died but what if Uzumaki Clan was there before ten tail attacked?
I think at the time of Rikkudo, his clan have not realized their potential. May be it was just him who knew about their true potential. And may be he was the one who created sealing jutsu and with that power he could seal the ten tail. Now after he sealed the ten tail, he got a new eye power and an infinite chakra which he used to create ninjutsu.
What do you guys think? You can add some more theories to support this idea.