Birthright - 4th Edition
After the Battle of Deismar and the death of the god Azrai, the lands of Aduria, the continent from which the five tribes originally came, fell into utter discord and anarchy. The nations that had been built under his power collapsed from a combination of weakness, rebellion, and power-hunger, several of the armies which had been under his banner having come from these lands only to be lost in battle.
In the two millenia since, nations have risen and fell, and many of the peoples have reverted to nomadic living, due to the poor quality of life remaining. For a time, empires from both Cerilia and Djapar have placed colonies. However, in both cases, the motherlands became unable to sustain those colonies and pulled back; thus the remnants they left behind have fended for themselves, each in their own way.