Countries
Most countries were destroyed after the corrupt plant life took over. The two main countries that stood above the others during this time were the US and the UK. While Canada attempted to survive after the failed creation of Alibucks it fell into ruin. The remaining refugees usually fled to other parts of the world.
When the sky cities were finally complete it was only the US, the UK and some parts of Asia that had them and all of humanity fled to these cities. the US had sky cities it would run along with the LDC, the UK had its own sky cities to run, and different countries in Asia combined into one to have its own sky cities.
When the Kaeraa war ended and humanity started to rebuild on the land it was decided between the three main lands that it would be more efficient to split the world into 3 main groups for each to run until the world became more stable, as a majority of everything on land was in ruin.