The dragonborn are the only race that is counted among the Common Races that is native to the Lastlands. When the other Common Races arrived to settle in the Lastlands, history says that they found small villages of dragonborn already living there and subsumed the inhabitants into their settlements. That is the argument for not counting dragonborn among the Common Races. However, it is also clear that many dragonborn came with the other settlers across the Endless Sea. They have needed to adapt to the Lastlands like all the other Common Races. To make it even more complex, these groups have intermingled and produced egg-clutches together. When faced with this level of complexity, sages of history keep debating, but most inhabitants of the Lastlands shrug and count dragonborn among the Common Races.
After all, dragonborn are the second most common race in the Lastlands, after humans. The most powerful person in the Lastlands, Autokrateira Manin, who rules unopposed over Firsport, is a dragonborn. Dragonborn mostly say they feel at home in the Lastlands. They are by and large against expanding further in the Outremer. They generally support the status quo. Despite their fierce appearance, only rarely will a dragonborn homestead in a new area or push into the wilderness. Still, whatever they do, they do it very intensely, with great focus.
Most dragonborn in the Lastlands are of mixed type; it is impossible to tell what color of dragon they descended from. There are occasional clutches or individuals that have a clear connection to one color of dragon, but it is quite rare.