Prologue

Two young wolf pups ran down the path in the forest. The dusty brown chased the gray."Hurry up, Rusty!" The gray called behind him.
"I'm coming!" Rusty shouted back.
The two littermates kept running. The forest flew past them. Finally, they made it to a makeshift house, built by twigs and leaves.
The gray looked at his brother, smiled, then stepped inside. Rusty followed.
"Airwing! Airwing!" Rusty shouted.
"Airwing!" The gray pup echoed.
The two pups walked into the next room over. An old, wise wolf with big wings looked at the pups.
"What is it, young ones?" He asked gently.
"Airwing, tell us about bending! I can't wait to be a bender!" The gray jumped up and down.
Airwing smiled. "Patience, Dust. You are a pup, and it will be a while before you can learn to bend. Enjoy being a pup while you can.
Too many wise words, Dust rolled his eyes. "Please, just tell us about the history of bending!"
Airwing chuckled. "Fine, fine. I will begin," he coughed, then continued. "Back before any of us were born, four animals joined together. One looked like fire. Another looked like water. The 3rd looked like the ground, for it was brown. The 4th and final was white, like the air. All four of them sat beside the Eternal Fire Stone-"
"Eternal Fire Stone?" Rusty gasped.
"No one has traveled there in centuries!" Dust added.
"Remember, this was before any of us were born," Airwing pointed out. He continued. "They sat beside the Eternal Fire Stone. The Bending Spirit appeared above the Stone. It granted the four of them powers if they promised to use them wisely."
"But why are the Firebenders evil then?" Dust asked.
"I'm getting to that," Airwing nodded. "The fire wolf's son became evil. That is why the fire benders are evil. Before the first benders' offspring were born, they taught bending to animals worldwide."

Author's Note:
Yeah, I don't know the story of bending in the cartoons. I just made it up! ^^