I think its pretty interesting. Amaterasu is the ultimate Katon, yes...but it was foreshadowed to some degree that Katons don't do jack against Chakra. (One-tailed Naruto vs Sasuke) Imagine a Greatball Rasengan clashing with Amaterasu flames? Burning through chakra? I dont see this happening. Sure, in the Sasuke vs Itachi fight it consumed a Katon which is chakra based but that was manipulated chakra which...I would say....EVOLVED the chakra too much from its raw state into a different form of matter all together. Hmmm....think Im off straying. Anyway, its like warm water and boiling water. Even though its hotter, The hot water cant "destroy" the warm water because, well...they're the same thing. Amaterasu is fueled by chakra so I dont see it burning something that FUELS it. e.g Naruto's Rasengan which is pure chakra or even his Kyuubi cloak. Don't wanna write too much I'm not too wise when it comes to the ins-and-outs of how things work in the Naruto universe so its easy for me to be absolutely wrong so thats why Im asking a question. So please, if you disagree with me, bring your points. I'm all ears.