Avatar: The Legend of Korra Book 2: Spirit
Whats nice about in Book 2:Spirits is the world building of the whole Avatar universe. This season we learn more about the myth and the origin of how it all begun. We learn about the story of Wan, the first Avatar. In the legend of Aang we learned how Aand stopped the war and bought peace to the world. In The Legend of Korra Book 2:Spirits we learn more about the actual avatar as to how the Avatar became the bridge between the spirit and the physical worlds. Wan was actually a thief who was banished from the Lion Turtle City because he stole the gift of fire from the Lion Turtle and becoming the first fire bender. Before the world was only divided in different Lion Turtle cities which consists of the different elements (fire,water,air,earth). After being banished Wan travelled the world and was able to meet different spirits and earn the gifts from the other Lion Turtles and mastering the four elements.