In an alternate reality of Earth, where the continents never broke apart, is where our story takes place. 

After an unexplained natural phenomena at 12:00 am on January 1st 2000, The human race began to make massive technological advancements, launching us into a technological revolution.

This technological revolution would end up being the spark to ignite the Third World War 3 decades later. With access to innovative new weaponry, influential world leaders became arrogant.
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The United States of America began a covert operation dubbed "Operation Unity" as they began their attempt to take over nearly all 3rd world countries. The pipeline in doing so starting with devaluing the countries' currency and taking over the market on their exports. Then, once the respective country was overwhelmed with debt, The US government would pose a deal to them under the guise of a large business.

They would erase their debt and completely buy them out, establishing a complete monopoly in this country. These "Mega Companies" would now be the ones passing laws and regulations in these countries, giving more rights to the businesses and taking them away from the people over time. 

This operation was kept secret from the public and was described as America "Helping less fortunate countries out of charity" 
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Tensions between the World Powers worsened. But as America descended into a capitalist dystopia, they already had substantial man power as well as advanced weaponry.

WWIII began in 2039 and lasted for 8 years. It was bloody and destructive, ending millions of lives and leveling entire cities to the ground. Most of the historical infrastructure from our time was completely decimated. The war ended in 2046 with China joining forces with America in a deal to have power in the new world government, the Corporatocracy. 

[A Corporatocracy defined as an economic, political and judicial system controlled by corporations or corporate interests.]

A new currency was adopted and they began to develop a new system, thus marks the birth of MEGACORP. The unified world government ran by the rich and powerful, the main conglomerates of China and America had created a power system giving them an insane monopoly of companies over the entire world. All countries that weren't under Megacorp's umbrella were lost to the ruins of war. 
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The northern parts of North America and Russia were left desolate war torn areas, and it became classified as the UNINHABITABLE ZONE while the rest of the world was repopulated and industry and construction began to boom.

Megacorp settled on creating a new headquarters in the west coastal region of China, which slowly became CENTRALITY. Industry and housing was built everywhere else and over time borders were forgotten, the world began separating into the WEST, EAST, NORTH, and SOUTH prefectures