Avatar: The Phoenix War

Historians say that a turning point in the Hundred Year War was when Azula, daughter of Fire Lord Ozai, successfully killed Avatar Aang through the use of lightningbending. While his friends tried to save his life, they failed, and the Avatar cycle was broken. Resistance against the Fire Nation's conquest of the planet crumbled quickly. The Avatar's friends, at least those that were still alive, aligned themselves with the White Lotus, an organization that embarrassingly had the former General Iroh in its ranks. The White Lotus made a last stand at the city of Ba Sing Se, but the battle occurred during the arrival of Sozin's Comet, giving the Fire Nation the advantage. The Fire Nation's airship fleet successfully burned the city to the ground, and the newly-proclaimed Phoenix King, Ozai, defeated his brother in single combat. A new era under the bright light of the Fire Nation had arrived. 

The Phoenix King proved to be a ruthless leader, mercilessly crushing any resistance to the Fire Nation's rule. The Fire Nation itself was placed under Prince Zuko, who was given the office of Fire Lord after Ozai relinquished the title. Meanwhile, Princess Azula was allowed to keep the title of Earth Queen, and was tasked with keeping the massive Earth Kingdom under Fire Nation rule. Ozai's decision to give his children these thrones was made in order to take advantage of the sibling rivalry and redirect animosity that might be directed at himself, and because Ozai was uninterested in such lowly micromanagement. The allocation of power suited his children's personalities: Zuko was a kinder individual who was useful in keeping Fire Nation loyalty, while Azula's ruthlessness was useful in crushing dissent in the Earth Kingdom. But ultimately, the children were just the puppets of the Phoenix King, ruler of the entire world.

When Ozai died in 160 AG, his empire quickly collapsed. Ozai was very unclear about which of his two children would succeed him, and neither wanted to acknowledge the other's claim to the title of Phoenix King. Azula believed that the title of Phoenix King was rightfully hers, as she had done more to aid her father in his conquest of the world and had remained loyal. Zuko wanted the title because he felt that his father had been overly harsh in his governance of the world, and he believed that his sister would burn the Fire Nation's empire to the ground, literally and figuratively, if she ruled. 

Zuko had quite a sound basis for this belief. Azula had become somewhat unstable after she was sidelined by Ozai after the Fire Nation's victory, and was angered further that her brother received the title of Fire Lord, in spite of her having killed the Avatar. However, she was more or less content to rule the Earth Kingdom, a far larger territory as her father constantly reminded her, and Ozai had even allowed her to burn the occasional earthbender if she so pleased. However, after Ozai's death, the fact that Azula wasn't explicitly given the title of Phoenix King served as the ultimate insult, and her already strained sanity snapped completely. Upon hearing that Zuko would not relinquish his claim to the throne, she declared war on him, and asked every Fire Nation noble and general to aid her in claiming the throne. In response, Zuko made his own call to arms. The Fire Nation's empire was split in two, and a new war had begun.

It has been ten years since Ozai's death, and the Phoenix War shows no signs of stopping soon. While forces loyal to Zuko are beginning to secure the Fire Nation proper, Azula still commands a massive army, and will likely fight desperately for every inch of land that she controls. However, in her madness, Azula has lost much of her actual political power. While she is still Earth Queen, actual governance of the Earth Kingdom has fallen to the Dai Li, who relay Azula's insane orders to the rest of the Earth Kingdom and Azula's loyalists. Often, these orders are mysteriously lost or change, and the Dai Li have taken steps to ensure that the Earth Queen only receives good news. After all, they know what happens to the bearers of bad news. 

But news for the Earth Kingdom is anything but good, because the truth is that the Earth Kingdom is crumbling. Many earthbending revolts are popping up throughout the countryside, motivated by a people tired of Fire Nation tyranny and seeing the opportunity that the movement of so many Fire Nation troops to far-off battlefields has given. To the far west, the Union of Equalist Republics has risen. Led by the enigmatic Amon, the anti-bending Equalists have taken advantage of the chaos and established their own nation, where bending is a crime punishable by death. The Equalists are making incursions into the rest of the Earth Kingdom, and the possibility of the entire Earth Kingdom falling to them is something that horrifies Fire Lord Zuko and motivates him to win the war quickly and contain the situation. 

Zuko has made promises to the people of the other two nations that he will restore their independence if they aid him in overthrowing his sister and fighting the Equalists. Zuko has framed this as a desperate measure, but in truth he wanted to dismantle his father's empire and would have done so from the throne of the Phoenix King had he gained it peacefully. This hasn't stopped some resistance movements from distrusting Zuko's intentions, particularly the resurgent Northern Water Tribe under Chief Unalaq. Unalaq is an ardent spiritualist, fearful of the imbalance that killing the Avatar, the destruction of the airbenders and and over half a century of Fire Nation rule has caused. There are rumors that a new Avatar, this time born among the earthbenders, is starting to become active, and some hope that this figure can bring balance back to the world.