Originally posted by Naija boy
Pain can develop new bodies like he did to Asura pain or whatever his name is. Also if iirc kamui is like a a suction attack where the target sucked into the dimensional hole. If so then pains shinra tensei is a very good attack to counter it as it deals with repulsion. Then theres the fact that shinra tensei is faster to use.Also if gai had been there from the onset i dont think pein would have allowed such a strong opponenet to live and since he wouldnt need gai alive for information he would have killed him quite early.
It never really explains how Kamui works but all Kakashi needs to do it get Pein to use his attack then hit him with Kamui right after. Its instant like Amaterasu. And sure Pein can make new bodies..if he has them in his tower, and back at the Rain Village. But not while invading Konoha. And the strongest body being gone would've done a lot.
And Pein didn't need to let Kakashi, Chouji, and Chouza live but they didn't die automatically. He stepped up his game a bit but Chouza only died because Chouji shouldn't be in a fight without being Butterfly Chouji. Just like Kakashi's reason he died.
Assuming either are really dead.
@Leon - It's really not fair to compare the two. Pein's is more of a force pushing everything away while Naruto's is more of an actual explosion. Though the explosion is probably stronger but I don't really know.