Firestorm can move at FTL speeds and can turn Natsu fire into water (or anything) if he feel like it
So Firestorm wins easily
Look man, just because two characters can manipulate fire doesn't make this a good match. This match is like putting Edward elric against galactus just because they can both transmute things.
First of all, Natsu isn't immune to all fire
Second, Firestorm doesn't just use fire
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