What is the limit for the Rinne Tensei?

Question

I know, that the Samsara of Heavenly Life is able to resurrect either all the individuals recently killed, or a single person from long ago. I know also, that this jutsu it's different from the Edo Tensei, since "It seems that this technique does not need the original body for the owner to be brought back, as Madara's original plan consisted of Obito reviving him at a time where the original body would have decomposed."

So the question is: does this technique have a weakness, or a time limit, after which you can't use it, or it's flawless?..If that's the case, could a Rinnegan user revive e.g. The Sage Of The Six Path?

Answer 1

Technically speaking, yes, the Sage of the Six Paths could be revived using this technique.

the technique targets either all the individuals recently killed, or a single person from long ago.

This technique can also be used on people brought back to life using Summoning: Impure World Reincarnation, transforming the debris and ash that forms the corpse vessel into a real body of living flesh and blood; even if they have been dead for many years.

But it seems to take a huge amount of chakra and be close to impossible to revive people without giving up your own life.

This technique seemingly requires a massive amount of chakra, risking death in the process, as Konan feared the worst for Nagato when he used it after having previously expended so much chakra. After using the technique, Nagato became severely weakened; his hair became white due to overexertion of his chakra. Obito's usage of the technique (even on a single target, as opposed to Nagato's use on a village's population) brought him to his inevitable death, as Black Zetsu noted. source