Aang was tired.
Staying up all night could do that to you
At this point he didn't care, not any more
He knew it was time, he'd spent several ours contemplating it until he reached his conclusion
He almost felt embarrassed, would people think that the youngest to master the elements was the first to go, Kuruk and Yangchen both lived into their hundreds, Kyoshi lived for even more, and if Roku hadn't been abandoned on that molten rock, surely he who have live longer, he laughed at that, probably not, he was too loyal for his own good, but then again weren't all avatars…
He'd always suspected that the iceberg had taken something out of him, but he was never sure what, now he was certain.
He got down from his perch on the roof, on the ground he looked around, at the side of the house their was a barn I which Appa slept, in through the window he could see Momo, the three of them were the remnants of a once great and peaceful nation,
That wasn't quite true; Momo belonged to this world, along with his friends, family and everyone else. He and Appa were from another, a hundred and fifty years apart.
He entered the house; it was hard not to think of what would happen once morning came. He kissed his wife on the cheek and exited into the barn.
Waking Appa up was easier than expected, it was like he could sense that he needed to go, that they needed to go together, sister Iio was right, a sky bison was a companion for life.
Aang jumped into Appa's saddle, airbending made is simpler, even in his old age
"One last time, right Appa, yip yip"
The ride took several hours, it was nearly sunrise when they decided to stop, a domed island with caves leading to the centre, Aang, knowing of Appa's discomfort under ground, flew over the small island, by chance, there was a circular hole at the top, they descended. The meadow was beautiful, it was sheltered from the rest of the world, and the grass was covered in small flowers. In the far corner there was an ancient tree, gnarled and twisted with over ground roots, each section between the roots was large enough to host a man, the tree itself was twice as tall as Appa. Appa landed and Aang got off, Appa closed his eyes and didn't open them. Aang lay back on the grass; one last fleeting thought entered his mind. He closed his eyes and departed into oblivion.
The sun rose over the horizon, filling the world with its warmth.