Is Rikudou Sennin the undisputed, strongest ninja to have lived?

[ringleader]

Yes he is anyone who says otherwise is just stupid
he was the ****** jinchuuriki of 10 tails
he had the rinnegan

 

[RokuNR]

Rinnegan users are like the Avatars of the Naruto world, so they have capacity to surpass anyone in every aspect. Pein was still inexperienced compared to Rikudou Sennin. I believe he was uber strong, more powerful than anyone else. xd

 

[Emperor]

Duh, of course he was, he had the Rin'negan, and the combined power of the Shukaku to the Kyuubi, plus the ability to seal away that much power.

 

[+luffy+]

he is legend ...and the strongest ever lived...he created countless jutsus
and and perfected them with his rinnegan...and also had the 10 tailed beast under his control...imagine how poweful he is....

 

[iannismatev]

naruto and kyubi never didnt beat nagato .......... at the time they met each other nagato could kill him ........... he can control the life and the death and he died to save the konoha people because he believed in naruto

 

[Steinbiz]

I was going to say no, but if the sage really fought on equal footing with the 10 tailed beast, then I guess nobody could stand up to him. That would be just stupid power. Take Nagato and multiply his power by like....5. Not even Minato could fight that.