Kishi may have actually screwed up this time/there HAS to be another tobi
I know you some of you guys are going to say "just wait to see what Kishi does" and I am, but I just really feel like this is something we should all seriously consider right now. Everything I'm about to say centers around the manga's timeline. Originally, this thread was supposed to be a theory on why Obito was really needed. But while trying to finish the theory, I couldn't put the final piece together because of this timeline error I couldn't help but notice. Please just read and feel free to correct me if I'm wrong. This will probably get long, so I'm warning you now. Stop here if you know you don't read threads anyway.
There are some things I want you to keep in mind as you read all of this. First of all, Nagato got his Rinnegan during the [B]second ninja war.[B] Madara met Obito towards the end of the 3rd ninja war. Also in the 3rd ninja war, Nagato is an adult fighting Hanzo with Yahiko and the original Akatsuki. There is about 2 decades (about 20 years or so) of time difference between the 2nd and 3rd ninja war. Meaning right now, while Madara is just meeting Obito for the first time, Nagato has been walking around with Madara's Rinnegan for about 20 years.
As I said before, this was supposed to be a thoery thread. Originally I was going to explain that Madara needed Obito simply to hunt down Nagato and get him to use RT for Madara again. I think 20 years ago, when Madara gave Nagato the Rinnegan, something happened that must've ended up separating the two, causing Madara not to be able to go thruogh with his plans of reviving himself with RT. Think about it, if he already had Nagato, he wouldn't have needed to wait 20 years to get Tobi unless something had happened that kept him from using Nagato like he originally planned.
So my thread was going to say that Madara needed Obito for Nagato. We know that RT can only revive someone who dies recently, and Madara is on a life support and will die if he comes off it. I think Madara must've pulled the plug thinking Tobi had secured Nagato for him again, but for some reason, he wasn't revived right away. That's why Edo Madara was so oblivious to the fact that Nagato was dead and had betrayed him. Madara took himself off life support thinking he was going to be revived minutes later. It also would explains why Yahiko thought so highly of Nagato. Remember Tobi told us that he was the one who convinced Yahiko to start the Akatsuki, meaning he had a lot of influence over him. He probably told Yahiko that Nagato had the power to revive someone who could bring peace to the world, and that's why Yahiko saw Nagato as the "key to peace". That is how Tobi was supposed to get Nagato under Madara's control again, by controlling his best friend, Yahiko, and we know Nagato would've done anything Yahiko told him.
All of this sounds good and flows well, except for one BIG problem. Yahiko was CONVINCED to start Akasuki. The Akatsuki was already started at the same time Madara is JUST meeting Obito, meaning Obito couldn't have been the Tobi that spurred Yahiko to start Akatsuki. Meaning that there absolutely HAS to be another Tobi helping Madara before Obito. Madara couldn't have convinced Yahiko to start Akatsuki himself because the Akatsuki was started during the 3rd ninja war, and as we know, Madara is stuck in that cave during the same war. The only explaination left is that there is another Tobi. Madara does currently have only one eye. He could be sharing that eye with someone else, who could be the other Tobi that's been helping him up until this point. But we know it can't be Obito, because he is just meeting him. And if there is no other Tobi helping him, then everything so far makes zero sense.