Kohaku

Kohaku (琥珀) is a dragon said to be around 10.000 years old, but he may as well be way older than that.

He lives alone in a shrine on a deserted island in japan. Why, or for how long, he doesn't remember.
He only remembers a promise, a promise to protect the forest there. He doesn't remember who he made the promise to, either.

Through the centuries, other dragons unruly children were often sent to him, to learn something from him cause he is seen as very wise in dragon society. Altough that practice is getting out of fashion more and more, so he doesn't get many visitors in more recent years.

One of his students was Li Yuan. Li still remains a friend to Kohaku to this day, and he greatly respects and looks up to his mentor and visiting im more or less regularly.
But even Li will one day forget about Kohaku. 

And once each and every dragon has forgotten about him, he will have to succumb to his fate to be alone for eternity.