Confused about Rinne Tensei, Ten tails Host and Rinnegan

[KCMNaruto]

Hello guys, I am curious and wondering for some time What Rinne Tensei really requires from the user ?

It is just chakra amount directly proportional from number of dead people and how much time passed since each of them died from user or it is something more as life force, as well...

I ask this because since Ten tails was introduced as infinite of close to infinite chakra monster.

Then Obito became it's host and could spam all the techniques... even although Kishi had to limit/hinder him from using Kamui(which he spammed a lot already ), but also Rinnengan techniques weren't used.

We know that Madara needs to be revived by Obito using Rinne Tensei for Madara to become Ten tails host...

Also It was confirmed that Obito as no host could die if he used Rinne Tensei....

But nothing like that was stated when Obito was ten tails host.... as far as I remember.

In SHORT

I am asking What The Rinne Tensei technique trully cost it's user ?

1) just enough chakra amount..., if this is the case then Ten tails Host Obito could revive anyone and survive... as he had infinite amount of it or close to infinite.

2) life force, then Being Ten tails host could not save him, but as Ten tails Host Obito could still live longer thanks to rapid regeneration of Ten tails + his Senjuu DNA. Only cost would be shorting his lifespan

3) Life force and amount chakra combined, then it could be though case but Obito still could surivive just a bit longer...

or maybe Hosts of tailed beasts can NOT use Rinne Tensei, same with Repear Death seal...

I wonder

Thanks for reading !

All replies will be much appreciatated

 

[SanjiNL]

Just chakra I think.

 

[KCMNaruto]

Just chakra I think.

If this is truth, then it is plot hole because Obito as Ten tails Host could spam Rinne Tensei and still live on...

unless Hosts are incapable to use Rinne Tensei, same as with Repear death seal