I'm pretty sure that madara knows kamui's weakness and remember that madara can use both rinnegan and ems techniques. I also think that obito won't kill himself to revive madara because he probably wants to be the juubi's jinchuuriki as well but madara probably thinks that he is willing to kill himself to revive him and he needs him alive after all so that's why he hasn't tried to kill him yet. I'm just saying that madara would win because obito hasn't shown anything besides kamui that can stop madara but madara most likely knows about kamui already so obito won't get him with that. The only way that obito would stand a chance is if he was the juubi's jinshuuriki imo.
How can he know the weakness when he haven't even seen it truly? We cannot come here and say Madara can use ton of EMS techniques we haven't seen, that is like me saying Sasuke can use perfect susanoo since he have EMS. Do you know why they don't try to kill each other? Because they are team even if they don't like each other, they have same goal and have to complete it. If they start attacking each other then the connection with the Ten tails will stop, and they will not be able to control it again. So you are saying Madara would win because Obito have not showed anything else than kamui? Well then, take a look at this.
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Etc, etc. Let's not forget the Rinnegan, if he can use Human path and Rinne tensei then I am pretty sure he can also use the other techniques as well. The only weakness of Kamui is another space time technique, for example Kakashi or Minato. We have not seen Madara using any kind of space time technique which means there is no weakness if they fight. If Obito suck Madara with Kamui, then it is pretty much over for him because he will not come out. Obito's reaction time is amazing, for example use Kamui when A is attacking with raiton punch.
So don't say Madara will win without any reasons, your post is tbh only BS because you're saying Obito only can use Kamui which is a shame.
Depends which Obito you're talking about. If it's Obito at his maximum with his Edo Jinchūriki paths, Gedō Mazō, 7 bijū and Rinnegan, then Edo Madara will be having the fight of his life.
If they fight 1 VS 1, then the Gedo mazo should at least go to the one we have seen summoning it, which is Obito. Obito's power is also to control the 7 bijuus.