Amerlain
Regular
If the fighting between factions lasts too long or past a certain year, there could be a chance that The Padishah's armies would show up in the east and start trying to conquer Calradia. It could be an event that would give factions a chance to ally together to face the menace, or possibly fall one by one to it. The armies could be large to compensate for not having a lot of territory to replenish themselves and could benefit from special bonuses that allow for them to have enough supplies at the beginning. The special parent faction could also have some economic bonuses to reflect how it is supported by a united empire that lies just beyond the borders to the east. Maybe this could be a DLC or maybe a mod.