KKnD

In the year 2079 conflicts arose between the major nations of Earth. A nuclear war resulted of this and the surface of the planet was destroyed. Some humans managed to burrow under the Earth's crust before the nukes obliterated the upper world, taking with them what they could salvage. They turned their attention to constructing machines to resurface. Those who survived the blasts yet lived above ground mutated, and dominated the Earth until the survivors broke through the Earth's surface and an armed conflict between the two groups erupted.