How big is the power gap?

[Narutp1sasuke2 LetsGo]

How strong is The Last Naruto in his Base Form?

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Compared to Him?

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[AlphaMaleLion]

Very big of course, Rikudou chakra is OP

 

[Defence]

Naruto fought a weak willed villain in the last. To see his true potential he needs a real test. Not madara though as that would be an over kill

 

[Chaosmark101]

I think a RSM Naruto clone with just 10-30% of his chakra could low diff "The last" KCSM Naruto that fought Toneri.
If Naruto is in base. That clone negs

 

[Holy God]

Adult Naruto without any extra powers has no chance against a version of him with the Six Paths Sage Mode.