Air...Water...Earth...and Fire.

After Tetsuo had dissolved the Earth Order, several different Earth states emerged, and the Earth Nation, made up of Ba Sing Se and the surrounding area, had declared its independence from the Earth Order.

However, Tetsuo's time had passed, for a mysterious organization called the Guang Society had recruited members from all over the world, and slowly grew stronger in numbers, whose sole mission was to bring peace to the world by conquering it by controlling governments, and they will stop at nothing until all world leaders are loyal to them.

There is a new hope nonetheless, for after Tetsuo lay to rest in the swamp, A Fire Nation princess was born, and her name was Kikyo, soon to be the first royal avatar since Korra.

I believe Kikyo can save the world.