I would like to make a correction or two, for the sake of completeness. The Ramagra (the undead elves with the banners) were not Dragon Mages, simply skilled warriors, rogues, templars, and scholars who had been imbued with various powers and eventually transformed. I have a partial list of which was what that I will take a look at later on.
As for how they came about, it is a bit of a long story, but confusion is cropping up with how it relates to Valerian because he was once part of a different formal magic that backfired. The Ramagra were not a backlash, but a purposeful creation, according to what I have been told.
That aside, Seronia and Titania are correct.
Telaris