My brother Aang and I are close. We grew up together as best friends. I was there for him when he was at his worst. I was with him when he ran away from the air temple.

I was with him when he froze himself in an iceberg.

And then the people in blue somehow got us out. I could tell that Aang immediately liked them, especially the girl. It was the first time that I ever thought about my brother getting a mate one day.

The people in blue were called Katara and Sokka.

Katara is very nice. Sokka is… funny.

Then we traveled the world, which had changed while we were frozen. We were attacked many times. I don't know why, but they seemed to want Aang.

Katara, Sokka, and I protected him. We protected each other. And it was okay.

We went back to the air temple to find nothing left but a lemur whom we named Momo. Aang and I were very sad.

We then traveled some more and found many difficulties. We made it through though.

Then, we picked up a blind girl who could see. She said her name was Toph and I liked her very much.

And we traveled more.

The people who shot fire at us chased us around the world. I was scared sometimes but I never left Aang.

Until, that is, I was captured by the people of the dessert. It was not my choice. They took me and I tried to get away, but I could not. I tried to go to Aang, but after a while, I had lost all knowledge of where he was.

And those people did horrible things to me.

I escaped though and found an old man who seemed to know the ways of my family. My family seems to no longer inhabit this world. He taught me how I could find Aang.

It was not easy getting to him though. After a while, I was finally with him again. I was so happy. He was so happy. He called me 'buddy' again.

And then we continued with our journey from where it had left off.

Aang got very badly injured while he was underground. I never liked it underground.

His skin smelled burned. It must have been those people who shoot fire.

Katara healed him though. But it took a very long time for him to get better. I was never more scared.

But all that was a very long time ago. All that was before the great battle with the people who shoot fire. All that was when I was young.

I am very, very old. And there is peace now.

Aang is not old though. He seems to be in his prime.

I do not think it is fair that I should age faster than he. It is not fair for him.

What will he do without me? How will I protect him when I am dead?

And I am dying. I can feel it. And it makes me sad. And it makes Aang very, very sad.

"Appa," Aang says to me now as I come out of my thoughts about the past, "please don't go. What will the world do without sky bisons?"

That's right. I never found a mate… Even when Aang did.

"C'mon buddy, let's go fly one more time." Aang walks to the ledge of the cliff.

He does not mean to ride on me. I have stopped being able to carry anything for a while now. He will glide beside me on his orange wings.

I slowly move to the cliff to sit next to him. I yawn wide.

I am tired. I will sleep first.

And I lay down. Aang seems to have tears in his eyes.

I lick him. Don't worry, I try to tell him. I'm just taking a nap.

He sits down next to me. He curls his fingers in my white fur.

And I close my eyes.