Migration is the international movement of people between the four nations. Although migration was relatively rare for much of history, the outbreak of the Hundred Year War saw the mass settlement of Fire Nationals in the Earth Kingdom, as well as large waves of refugees attempting to escape the war. With the war's conclusion and the establishment of the United Republic of Nations, migration started to become increasingly common across the globe.
Being inherently migratory people, the Air Nomads frequently moved between the other three nations and the air temples, although they were a relatively rare sight in rural parts of the world. Air Nomads were considered bearers of good fortune and were often welcomed with hospitality in exchange for help with chores, news, entertaining stories from other parts of the world, or relaying messages to distant relatives. They were frequently asked for blessings whenever they arrived at a village, thanks to their spiritual way of life. The Air Nomads also accepted pilgrims from the other three nations visiting the air temples. Occasionally, they came to permanently settle in another nation if they were exiled for defying their people's nonviolent way of life, such as Kelsang and Jesa.
After the Air Nomad Genocide, the air temples remained abandoned for the duration of the Hundred Year War. However, in 89 AG, the Northern Air Temple was rediscovered by a group of Earth Kingdom refugees led by the mechanist, settling in the temple after their village was destroyed in a flood.
At the war's end, Avatar Aang built a new Air Nation consisting of Air Acolytes from the other three nations, after he reformed the Official Avatar Aang Fan Club in 101 AG. The Air Acolytes came to populate the restored air temples around the globe, as well as the new Air Temple Island off the coast of Republic City.
Following the Harmonic Convergence of 171 AG, the Air Nation welcomed new airbenders from the other nations after nonbenders across the world began to manifest newly acquired airbending abilities. After the insurrection of the Red Lotus, the Air Nation fully returned to its nomadic roots, but resolved to actively bring peace and balance to the world through relief efforts in the lawless Earth Kingdom, as well as helping to defend Republic City and aid evacuees during Kuvira's invasion of the United Republic of Nations.
In ancient times, a large group of warriors, waterbenders, and healers from the single Water Tribe journeyed to the South Pole after a period of civil unrest. These colonists founded a new tribal confederation of several autonomous chiefdoms, becoming the Southern Water Tribe. After some time, citizens of the Southern Water Tribe also came to settle in the Foggy Swamp in the Earth Kingdom, becoming a distinct tribe with their own culture.
During the antebellum period before the Hundred Year War, migration between the Northern and Southern Water Tribe was common enough that many members of the tribes had family and friends on the opposite side of the globe, reuniting with one another during the New Moon Celebration. Additionally, there were citizens of Water Tribe descent present in the Earth Kingdom during the early life of Avatar Kyoshi, such as Kirima, a waterbender who resided in Port Chameleon Bay, but had largely adopted Earth Kingdom culture and style of dress.
Although the two tribes drifted apart during the Hundred Year War, there was still some migration between tribes, as evidenced by Kanna, who fled the Northern Water Tribe for the South Pole to escape her arranged marriage to Pakku. A few select Northern Water Tribe natives attended Ba Sing Se University as exchange students during the war's later stages. One of these, Malina, later stated that she had spent more time in the Earth Kingdom than at the North Pole. Waterbenders in the rural Earth Kingdom were also not entirely unheard of, evidenced by Jiang's search for a waterbender in the spring of 100 AG. Following the Siege of the North, Pakku and a handful of volunteers from the Northern Water Tribe journeyed to the South to help rebuild their sister tribe.
After the end of the war, many Water Tribe citizens left their homeland to find economic opportunities elsewhere. Niyok and Nutha of the Southern Water Tribe came to work at the Earthen Fire Refinery, in the area jointly governed by the Earth Kingdom and Fire Nation. As more factories and businesses were established in the area that came to be known as Cranefish Town, more Water Tribe nationals arrived seeking opportunity, including several waterbenders. This trend continued as the town grew into what eventually became Republic City, with the United Republic's Water Tribe diaspora being represented by two members of the United Republic Council. By 170 AG, there was a Southern Water Tribe Cultural Center established in Republic City, as well as the Red Monsoon Triad that solely consisted of waterbenders. Other towns in the former Fire Nation colonies, such as Yu Dao, were also settled by newcomers from the Water Tribe. Water Tribe descendants, such as Ahnah, were persecuted by the Earth Empire following Kuvira's seizure of power.
Similarly, the Water Tribes became more cosmopolitan following the end of the war. The Southern Reconstruction Project and the discovery of crude oil in the Southern Water Tribe led to investment from the other three nations, although this was unsuccessfully opposed by Gilak and his Southern nationalists. By 171 AG, international citizens regularly visited the Southern Water Tribe, partly owing to Varrick's international shipping company.
Before the Hundred Year War, Earth Kingdom citizens were generally suspicious of outsiders from other nations and other parts of their own nation. Residents of Yokoya were prejudiced against Kyoshi as she lacked blood ties to the village and expressed displeasure at Jianzhu's Gan Jin heritage. However, Jianzhu did successfully manage to establish something of a cosmopolitan bubble at Yun's Avatar mansion, hiring guards, servants, and inviting guests from not just other areas of the Earth Kingdom, but also the other three nations. Large cities such as Ba Sing Se or Omashu also interacted with foreigners more regularly due to trade, with the waterbending master Amak finding employment in the Earth Kingdom's royal family.
The criminal underworld of the daofei was somewhat more accepting of outsiders, but the Flying Opera Company was a notable exception in having bending masters of other nations such as Jesa and Kirima, most societies being largely comprised of Earth Kingdom nonbenders. However, a lightningbender, Xu Ping An, managed to become an extremely notorious daofei leader during the Yellow Neck uprising.
In 37 BG, the Fire Nation began to establish colonies in the Earth Kingdom under Fire Lord Sozin's rule, although this project came to a halt after Avatar Roku confronted the firebender. Regardless, several of the early Fire Nation colonists stayed in the Earth Kingdom. Nearly four decades later, more colonies were set up following the Air Nomad Genocide and the invasion of the Earth Kingdom. Fire Nationals in the Earth Kingdom established new settlements, while a Fire Nation ruling class controlled cities such as Yu Dao and Pohuai.
As the war progressed, waves of refugees left territories occupied or threatened by the Fire Nation to protect other regions of the Earth Kingdom. Jin's parents and Liling were among those who migrated to Ba Sing Se in the later decades of the war. Hidden stations and transport hubs such as Full Moon Bay were established all over the Earth Kingdom to house refugees or provide transportation to sanctuaries such as Ba Sing Se. Despite the relief efforts, passport officials required refugees to have meticulous documentation to board ferries, forcing less fortunate refugees to travel via dangerous routes such as the Serpent's Pass.
In the final year of the war, there were still active waves of refugees, such as the Gan Jin and Zhang tribes, who sought to cross the Great Divide to reach Ba Sing Se. Another wave arose after the Surrender of Omashu and the eastward advancement of the military of the Fire Nation, including the cabbage merchant, the Freedom Fighters, Zuko and Iroh, and Than and Ying's family. Upon arrival, the refugees were made to settle in the city's Lower Ring. After the Coup of Ba Sing Se, some civilians were able to flee the capital for the last remaining strongholds resisting the Fire Nation.
The war's end led to the Harmony Restoration Movement, hoping to return Fire Nation colonials to their homeland. However, Fire Lord Zuko retracted his support after seeing how well-established Fire Nation culture was in the colonies, threatening war between the nations. When the Earth Kingdom and Fire Nation renegotiated, they agreed that the area ought to be governed bilaterally. The colonies consequently attracted new migrants from across the world who were seeking work and a better life. The area was later ceded to a new nation, the United Republic of Nations, although numerous Earth Kingdom politicians would resent this decision in the ensuing decades. Citizens of Earth Kingdom descent were numerous in Republic City, and Earth Kingdom citizens continued to migrate to the United Republic after its establishment. The Earth Kingdom also received immigrants from the Fire Nation, Water Tribes, and United Republic, though they were discriminated against during the rise of the Earth Empire.
Prior to the Hundred Year War, it was rare to see foreigners in rural areas of the Fire Nation. Atuat and Jinpa stood out as being from the Water Tribe, and Air Nomads in North Chung-Ling in 295 BG: Atuat was presumed to be rich, being able to travel long distances, and traveling Air Nomads were considered to be good luck. However, larger cities such as the capital were more cosmopolitan: Foreigners were less noteworthy at the royal palace, though flying bison were a rare sight for Fire Nationals. Additionally, several Fifth Nation pirates were of Fire Nation descent, having moved to the eastern South Pole.
Shortly before and during the Hundred Year War, many Fire Nationals left their homeland to settle in conquered territories in the Earth Kingdom. It was permitted for citizens to travel between the colonies and the Fire Nation proper, although inhabitants of the homeland often held a stigma about colonials who returned to the Fire Nation. Many prisoners of war were moved to the Fire Nation during the conflict, most notably the captured Southern Water Tribe waterbenders. In many cases, the prisoners were used as slave labor in the Fire Nation's coal mines. In rare circumstances, free citizens of other nations managed to settle in the Fire Nation, such as Hama, who settled in a rural village after escaping a Fire Nation prison, or Rafa and Misu, who journeyed to Forgetful Valley from the Northern Water Tribe, searching for the Mother of Faces to restore Rafa's stolen face.
After the war ended, a debate arose whether Fire Nationals should leave their nation's occupied areas. Initially, Fire Lord Zuko, Earth King Kuei, and Avatar Aang agreed to the Harmony Restoration Movement, transferring the colonials back to the Fire Nation. Though more recent colonies complied, it elicited objections from more established colonies, such as Mayor Nishi's village and the Fire Nation's first colony, Yu Dao. The intertwining of Earth Kingdom and Fire Nation cultures was brought to attention when Kori Morishita, a devoted Fire Nation citizen who was also an earthbender, attempted to assassinate Fire Lord Zuko. After traveling to Yu Dao and seeing this for himself, Zuko abandoned the movement and came to believe the colonies should be reformed rather than disbanded. This provoked the Battle for Yu Dao between the Fire Nation and the Earth Kingdom before it was interrupted by the Yu Dao Resistance and Avatar Aang. After the Fire Lord and the Earth King began renegotiations, they agreed that the colonies could not belong to either nation, beginning to establish coalition governments.
Fire Nationals began to migrate to the Yue Bay area soon after the establishment of the Earthen Fire Refinery, with a numerous population by the time it had grown into Cranefish Town. After the formal establishment of the United Republic of Nations, some Fire Nation citizens continued to immigrate to the new nation, such as Naoki, a first-generation Fire Nation immigrant.
United Republic of Nations
The United Republic owes its existence to the settlement of Fire Nationals in the Earth Kingdom, leading to a coalition government that eventually gave way to an independent state. Founded upon the notion that the nation would be a place where benders and nonbenders could live together in harmony, the capital of Republic City is cosmopolitan and is home to people descended from all of the traditional nations. Before 171 AG, the nation was governed by a council that represented the other four nations of the world. However, a stigma did start to develop concerning newer immigrants among the established populace, as members of the Triple Threat Triad belittled Avatar Korra as "fresh off the boat".
The population of Republic City is large by world standards, and the mass influx of immigrants from the four nations has caused considerable demographic challenges. The foremost of these challenges is inequality: the wealth gap is considerable. Newcomers to the city appear unaware of these phenomena until their arrival when presented with a considerable surprise. The Avatar herself believed its citizens to all be "living it up" and was shocked to discover vagabonds in the city park. With these difficult conditions, the populace seems ready to be stirred into a revolt against the perceived bending elite.
Tensions occasionally rose between the nation's residents due to political conflicts between the other nations of the world. The Northern and Southern Water Tribe communities clashed after the South rebelled against Chief Unalaq, and there was avid support for Kuvira among the city's Earth Kingdom population, even after she was denounced by President Raiko.
Some citizens of the United Republic moved abroad after the nation's foundation. One notable example is Suyin Beifong, who left Republic City following her arrest for petty crime, eventually founding the Earth Kingdom city of Zaofu.