The best way to fight an overpowering colonizing force is to set a mad disease loose in their camp. They've allied hundreds of small city-states into a massive force capable of wrecking intense destruction on all of the native forces, but not if they kill themselves first! Make their own people drive them mad with your chain virus and buy upgrades to make it deadlier every time.

Use your mouse to click on the soldiers and infect them with the virus. Watch chaos ensue!