Once-mighty predators of the sky, undone by cruel spellwork, the Dragonborn seek to return themselves to their grand state as masters of sky and land.
Here’s a short history. The Dragonborn now have a caste system in place; the tattered remnant of the Hunting Cadre that first rained down on Nor holds to their old ways. The Pure Dragonborn are automatically elevated above the Mar Dragonborn. The Pures are separated from the Mars based on eggshell banding and scale coloration at hatch time.
Only Pure Dragonborn can be rulers—Marred Dragonborn are used (at best) as shock troops, and menial workers at worst.