Arkhosia was a once powerful Dragonborn Empire, ruled over by the mightiest of Ancient Wyrms.
One thousand years ago its armies marched against the city of Bael Turath which ultimately lead to the downfall of both empires. When Bael Turath suddenly vanished from the battlefield, taking with it the Dragon Kings of Arkhosia, the Dragonborn empire was thrown into disarray. Infighting and power-struggles eventually lead to an all out civil war, Dragonborn against Dragon. The empire collapsed in a matter of years.
The Vanguard are a remnant of the original armies that marches against Bael Turath.