Military action
After a planar tear pulls a piece of the Draconic homeworld into Gyrraholm, it's Chromatic inhabitants seize the opportunity to expand and claim the new land as their own.
The second of the recorded Planar Tears caused by the surging Maelstrom at Gyrraholm's core, this incident did not simply displace a people, but an entire land mass. Assuming these planar immigrants would be as scared and confused as the elves and gnomes before them, the people of Valoreign extended open arms to them in welcome. But this corner of some far flung Kingdom, ruled over by a council of Chromatic Dragons, saw this as an a chance for expansion, and launched a full scale invasion of the Valoreign. Armies of Chromatic Dragonborn warriors and Drake Cavalries flooded the southern reaches of the isle, taking land and slaves as they went. Their rampage was only quelled by the intervention by a rival force from the Draconic homeworld, similarly pulled through the veil by a Maelstrom surge a 3 months later.