The Last Firebender is an Avatar AU by clockworkchaos. In it, the genocide of the Air Nomads failed, and the combined forces of the Air Nomads, Earth Kingdom, and Avatar brought the Fire Nation to its knees.
This story stars Azula, Katara, and Sokka trying to defeat the forces of the Air Empire.
Unfortunately, this fic has been discontinued.
- Adaptational Heroism: Ozai appears to be this, and Hama is a Hero Antagonist. Azula is the protaganist, just to drive the point home.
- Civil War: The Southern Water Tribe is apparently undergoing one of these, between the side allied with the Air Nomads and the side that isn't. Katara, Sokka, and their tribe are on the latter side.
- Defector from Decadence The Blue Spirit is this to the Air Nomads.
- For Want of a Nail: Aang never fled, leading to a chain reaction that led to the present day.
- Genocide Backfire: The Fire Nation's attempt to massacre the Air Nomads led to the Fire Nation getting the crap beat out of them.
- Gray and Gray Morality: Even more so than in canon, given that while the Air Nomads are technically replacing the Fire Nation, they're far more kind to their enemies and civilians than the Fire Nation was in canon, and their main reason for fighting is because they believe the Fire Nation to be utterly aggressive in attempting to wipe them out. The Southern Water Tribe is in a civil war between those who support the Air Nomads and those who do not, the Fire Nation is using propaganda to make it seem they are winning the war but most of the adults just want the fighting to end, the Northern Water Tribe is staying out of the war, and the Earth Kingdom, while not in a civil war, is still divided between those who do and don't support the Air Nomads.
- Heroic Sacrifice: Iroh attempted to pull this by challenging Aang to a duel he knew he had no hope of winning, hoping his death might bring peace, satisfy the spirits, or appease the Air Nomads. It didn't work.
- Hit-and-Run Tactics: The Air Nomads do this a lot, striking the Fire Nation and retreating before they can regroup and hit back.
- Not So Stoic: Jamayang was outraged when he discovered his ex-student Hariti was using his teachings to enslave Hei Bai and terrify Aunt Wu's village.
- Original Character: There are several of these, mainly among the Air Nomads (for obvious reasons).
- Poor Communication Kills: This was arguably responsible for the later parts of the war occurring at all.
- Superweapon Surprise: The Air Nomads as a whole are this: after the Fire Nation attacked and wiped out half their people, over the course of the next hundred years, the Air Nomads crushed the Fire Nation. Granted, the Earth Kingdom helped drive the Fire Nation out of their initial colonies, and Aang prevented any major counterattacks by the Fire Nation, but still, the least populous nation in the world took on the largest (united) and most technologically advanced nation without the Avatar or anyone else backing them offensively. And by the time the main story started, they had pretty much won.