So we can actually say that Obito > Rikudou Sennin? Because does not Madara have same abilities as Rikudou Sennin now has? Perhaps not.
Because what could otherwise Rikudou Sennin hit him with mhm...
*mindfuc* lol
Perhaps sealing jutsus still works on Obito.
Obito is no where near Rikudos power level same goes for Uchiha Madara.
We havent seen Rikudos Powers so we cant draw the conclusion about hes powers being the same as Madaras.
But it has been hinted , that he had the best Yin Yan manipulation ever = Creation of all Things.
Able to divide Juubis near infinite power into 9 parts and breath life into these 9 parts is a paradoxal and ihuman event in Naruto History.
Also supporting on Nagatos claims.
Chibaku Tensei created by Nagato was able to make a stone structure to hold off 6 tails Naruto but Failed at Narutos 8th Tail Transformation.
But Nagato Hinted , that he was capable of creating another Chibaku Tensei able to Hold off Narutos 8 Tails Transformation.
So Rikudos Power was able to create the moon by Lifting The Oceans floors and Mountains to form the Moon and not only that but to send the Moon off to space into a safe orbit so it wont fall back to Earth.
We are talking about something so powerfull that cant even be measured with Nagatos feats.
And all of this was done when Rikudo Sennin was over hes 60's and well over hes Prime 30-35.
Also it was done after Juubi was extracted from Rikudos Body so Rikudos lifespan was reduced to few days if not few hours.
The Reason why Rikudo Sennin defeated Juubi was because he was stronger than Juubi itself and was able to out perform its ablities or counter the abilities.
Im not saying that Rikudo defeated the Juubi without receiving a scratch.
But Rikudo indeed defeated the Juubi to a point when Juubis stamina was exchausted and it could not fight back anymore and thus Rikudo had the chance to seal it.
So we cant draw these conclusions until we have seen Obito or Madara perform : COAT or Chibaku Tensei in order to create a second Moon.
But it's Possible , that Madara will use a lesser version of COAT to perform Infinite Tsukiyomi.
Or some other version of this Yin Yan release jutsu.
Also it has not been hinted if Rikudo was able to perform Mokuton.
But if you take into account COAT then Rikudo could create forests with this technique.
Or Create humans.
Birds.
Insects.
And even bacteria with this technique.
Since all life organisms support chakra therefore can be built using COAT jutsu.
Also with COAT it could be possible to make perfect clones of a person.
And even Revive people from the dead.
It holds no limits.
Give enough chakra to the technique and could destroy the whole Universe.
Or when applied Via genjutsu could be used for Infinite Tsukiyomi.
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On topic.
Itachi and Obito are the best opponents to Counter Madaras techniques.
But we cant draw any conclusions on it.
Madara could have a Counter for Kamui.
Madara could have a Counter for Totsuga Sword.
Wont surprise me if Madara was the Former master for the Sword but was lost during the fight with Hashirama if So then How Hashirama countered the sword.
I think , that the sword is unable to seal Mokuton Abilites therefore Mokuton clones or even people who have Hashiramas power.
Reason why I believe this is because.
The Totsuga sword was created by TYS of the Rikudo Sennin.
It is a Spiritual Weapon and its Physical form is unknown if it even had any.
TYS could have been Original Mokuton user.
Having hes fathers knowledge about Yin and Yan releases he could have easily crafted such a weapon if not a number of them.
Also with the sword came a seal a special one for that matter.
That could seal away every oponent.
TYS knowing this added a second seal for safe measure if the sword where to fall into the wrong hands and be a danger to himself.
He added a seal to prevent mokuton users being sealed in that sword.
Thus Mokuton users where immune to its effects so some people from TYS lineage where safe and could oppose TES lineage if they where ever to came into possesion of this sword.
Kamui
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We cant be sure if Kamuis dimension traps people into the dimension forever or if there is a time limit for someone to be in there.
After some time a door could open and a person could leave the dimension.
Maybe the dimension does not support life forms for a long periods of time since they disturb its dimensional space and make it become unstable thus opening doors to leave this dimension.
The dimension looks abstract and surreal for that matter.
It could have infinite dimensions.
But maybe a Rinnegan user can leave this Dimension using Chibaku tensei to alter its gravitational field and ripping the space thus making a door to leave the dimension.
Also Nagato could be an oponent for Madara.
But not as Solo but with 6 paths of pain.
6 paths of pain is OP combination and is strongly underrated.
The only reason why Naruto defeated these guys was thanks to plot.
If the manga had a different course of developement and 6 paths of pain where to fight Epic figures like Orochimaru or Hiruzen Sarutobi then we could have seen their power on a larger scale.
Also to mention Nagato in Yahikos body was able to Destroy the whole Konoha in few seconds...
Nagato could actually have a chance of beating Madara.
But Madara will most likely win the fight with a trick from hes sleeve.