When the Hundred Year War came to an end, there was a sense of hope that somehow, despite the chaos and struggle and suffering of the last century of conflict, the world could return to the pre-war era of peace and international tranquility, that the return of the Avatar, the withdrawal of the Fire Nation from the western Earth Kingdom, and the restoration of order between the Four Nations could put things back to the way they had been long ago. This was a hopelessly naпve dream, as the world had been so utterly changed that it was impossible to return to things as they once were, at every level of life and society.

No better place is this demonstrated than the last 5 years alone. Immediately after the war ended, the Earth Kingdom and Fire Nation, the primary belligerents for much of the war, embarked on the Harmony Restoration Movement as a means to re-establish peace between them. This took the form of all Fire Nation colonials withdrawing from the western Earth Kingdom in advance of the region being returned to Earth Kingdom rule, but this was easier said than done. Many of the Fire Nation settlers had intermarried with Earth Kingdom natives and established lives so intertwined and settled into the region that they represented something that didn't align with any of the nations, and so the decision was made to more thoroughly debate the matter. The end result is a transitional plan to remove the colonies from any nation and form a Fifth Nation where all benders and nonbenders of any nation could live in peace. This has still resulted in conflict between established interests and the idealistic goals for these colonies, but nonetheless it proceeds.

At the same time realignment within the existing nations has been taking place. While Earth King Kuei has been facing general success in reestablishing the rule of the Earth King after it was eroded to the point of irrelevance during the war, Fire Lord Zuko has faced many challenges to his reign from forces loyal to former Fire Lord Ozai and the jingoistic, nationalistic order that he represents, despite being imprisoned and having had his bending removed by Avatar Aang. The New Ozai Society has constantly harassed the Fire Nation's efforts at dismantling the wartime state and efforts from figures such as Princess Azula have instilled fear in those who support the young Fire Lord's policies. Still, Zuko remains determined to continue with the path no matter how difficult it becomes, continuing forward with the assistance of Avatar Aang and other allies gained during the course of the War.

Significant changes have affected the Water Tribes and the Air Nomads, though the latter is not the same nation it once was. As Avatar Aang currently remains the only Airbender alive, the new Air Nation is composed instead of the Air Acolytes, non-airbenders who have nonetheless dedicated themselves to continuing the teachings and cultural practices of the Air Nomads as taught by Avatar Aang, and who have dispersed among the Air Temples to maintain the ways of the once extinct culture. Similarly the Southern Water Tribe, thoroughly devastated by the war, has been extensively reconstructed through the efforts of the Northern Water Tribe, but largely in the image of the Northern Tribe without much care for the original culture and practices of the South as a distinct entity. Though there have been efforts towards realizing this rebuilding of the pre-war South, the simple reality is that the South cannot simply become what it once was, because almost no one remembers it as it was. Thus, the South continues as a semi-reflection of the North.

Everything is different. The old way of the world is almost completely gone, destroyed in 100 years of war and carried on only in the stories carried down through the generations. Though there are many people happily and eagerly adapting to the rapid change and the new order of the world, just as many feel an unease with the changes, that somehow the world is no longer as it once was or as it should be even if they've never known anything different. Some try to appeal to the past as with the Southern Water Tribe and the Air Acolytes, while others eagerly face the future as with the former Fire Nation Colonies and the Fire Nation itself. Technology has begun to advance at a breakneck pace, proliferating from the Fire Nation through the world to the extent that entire cities can change seemingly overnight. Steam trains, airships, powerful war machines, and even changes in bending itself with the spread of the techniques of bloodbending and metalbending.

Whether for good or bad, the world will never again be as it once was. So it is.

https://www.deviantart.com/mobiyuz/art/Avatar-The-Last-Airbender-The-World-105-AG-859008793