how the fuck did the fire nation beat fucking anyone their element can't do shit to any of the others
shoot fire at an airbender? they blow fire back in your face now you got burn face
a waterbender sends a wave at you and you defend with fire? congrats dipshit now you've turned that attack into steam in your eyes at best or boiling water on your skin at worst
you throw fire they throw rock you get hit with hot rock war over
Literally the only way the fire nation fought enemies was with slow technological veachiles (drills and air boats) and fucking AMBUSHING PEOPLE. AND IT WAS MAINLY AMBUSHING CIVILIANS (against the Geneva Convention). The fire nations army is full of war criminals
You think they have the Geneva Convention in ATLA? They don’t even have Geneva.
sozens comet granted the power of sustained flight. thats how they got to the air temples. and as aang stated, the air nomads didnt have any military. between their pacifist ways and the surprise attack the fire nation did, it was a massacre. that isnt to say the airbenders couldnt defend themselves. there were multiple firenation corpses at the airtemple so at least a few of them were able to put up a good fight against the comet empowered firebenders