I really don't why everyone's got their panties in a knot. Kakashi asked "How come until now...?" he didn't say why are you planning to destroy the shinobi world. Sounds like Kakashi was going to ask something like "How come until now we didn't know you were alive" not what everyone thinks. Akatsuki didn't really mobilize till naruto returned to the village; which was what? roughly 19-20 yrs (just a guess) after I'll say obito's body was left in the rock pile. So Obito crushed and Tobi was revealed with a 19-20 yrs spread and you think that a girl/love dying alone would cause someone to go about the way he has? No. I think he answered "Because you let Rin die" as a way of saying to Kakashi that he doesn't care for him anymore.
As for Madara and Obito's relations it's interesting and I don't think it's Izuna because Madara would respect his brother more than to call him Obito considering the character doesn't care about what he is called. I'm more curious as to what happened to the Kages, they pass out again from the flower Lol?
Watch now Orochimaru and Sasuke and gang will show up and it will just turn into a three way fight or some crazy thing involving ridiculous fight scenes and various flashbacks to the point where Naruto comes out on top or dies along with sasuke
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Also anyone have an idea what the fire tech obito used is translated in english?