Disclaiming Banner: Possibly the only thing that I hate more than not owning something so cool as ATLA, is my %*#&# spell checker.
Immortal
The first human fire-bender had been forgotten by the rest of the world. But the Sun Warriors still remembered. Every year they gave a festival in commemoration of how he won the right to learn from the dragons. Their children learned his story in infancy and their elderly insisted the words were engraved on their very bones.
He had kindled the First Fire, and they kept it with the knowledge he would return every hundred years in celebration. In the outside world, his spirit had been renamed Sozin's Comet; but his children still knew him as Tien Hsien.