1. The princess of the Northern Water Tribe runs away to the southpole because she doesn't want to marry the prince. The king of the Northern Water Tribe is furious and is determined to get her back so he launches war against the Southern Water Tribe
2. There is a huge gold mine found in the Earth Kingdom, but the four cities, Omashu, Ba Sing Se, Aun-twe and Garsai have war over the gold.
3. The four nations were united under one king. But one king gave birth to an Airbender, a Firebender, a waterbender and an earthbender. A scuffle was made when the king died and all the sons wanted the throne. So each son gathered an army and broke a civil war the lasted 500 years. Eventually, the world turned into four nations again.
4. The Fire Lord was very cruel and very selfish with his decisions. Soon a large group of antigovernment people waged war on the people loyal to the firelord.
5. A monk of the Northern Air Temple wanted to make the Air Nomads into a complex monarchy. But the Air Nomads resisted because they wanted to lead a simple life. So tyrant and his followers forced rule, untill the Air Nomads decided to fight back and made war upon his followers.
