The Final Mourning
Dragons in Eberron aren’t quite the same as presented in the Monster Manual. There’s no particular correlation between color and alignment or even temperament, for example.
Scholars in Khorvaire will tell you that dragons live in Argonessen, a continent to the southeast of Khorvaire, and they’re very seldom seen elsewhere. They are powerful and dangerous creatures, always scheming, and they don’t handle frustration well. Some dragons can take the form of humanoid races, and often do if they need to travel to Khorvaire or Xen’drik, but the conspiracy theories about Khorvaire’s elite being dragons in disguise hold no credence. However, it is known that many of the dragons in Argonessen are obsessed with some grand cosmic scheme that only they can understand, and they sometimes send agents to other continents to make sure things play out according to their inscrutable plans.
More dedicated scholars believe that the mortal dragons are somehow related to the great dragons of Khyber, Eberron, and Syberis, perhaps as some sort of elder race. The kobold, dragonborn, and lizardfolk races also claim some draconic ancestry, with a greater or lesser degree of substantiation.