The War of Night
There are only stories of the fabled Dragon Riders. Fragments of history, scraps of knowledge. What is known however, is that they rode chromatic dragons, and were a force for good in the land.
Were they killed off by the undead threat? Evil Dragon Riders? Or did they simply no longer provide a function and drifted away? Regardless, it has been well over a thousand years since the last recorded sighting of a Dragon Rider.