The Ultimate Fire Master of Avatar

Those who can manipulate one of the elements—water, earth, fire, and wind—are called Masters, and thus the world has four nations and tribes: Water, Earth, Fire, and Air.
Only Avatar can control all four elements simultaneously, serving as a bridge between the four kingdoms and maintaining the balance of the world.
However, a hundred years ago, Avatar suddenly disappeared, and the Flame Kingdom, one of the four kingdoms, launched a war of aggression against the other three kingdoms, which lasted for nearly a century.
Just then, Kahn transmigrated and became a young fire master...