There is information about him, albeit his name was never mentioned.
In Itachi Shinden: Book of Bright Light
“My dad died in Nine Tails’s attack.” .. “Oh! My dad’s not an Uchiha. My mom’s Uchiha. After my dad died, we came back to the clan, and I became an Uchiha, too,” Izumi told him, as if reading his mind.
It's explained here:
Naruto is able to overcome these flaws by learning Senjutsu. By coating the Rasenshuriken in Senjutsu chakra, its shape is maintained after formation, meaning that he can use it as a projectile and, as a result, that he no longer needs to worry about damaging himself.
I'm not sure if this was explained in the anime since I only ...
The Sage of the Six Paths had the power of bringing illusions to reality. Obito explains this when he's talking about Danzo's Izanagi. You can say the ultimate Izanagi is that of a person who's combined Senju's power and Uchiha's power which is the power of Rinnegan, so I'd say Rinnegan has the unlimited Izanagi ability.