Equestria was never the same after the bombs. But one thing it left behind, aside from a desolate wasteland, was a new world. Magic became the way of Equestria in the east. And science, technology, became the sword of the west. In the center, however, in the midwest and the north and south, lay an entirely different danger. When the war ended with the meganukes, the remaining elements of harmony were shattered.
With harmony gone, only sin remained. Evil took hold of Equestria and amassed for centuries, undisturbed by time itself. And, as evil festered, it separated into noble sin and pure sin. A land twisted and malformed by it's own childen, Equestria rumbles awake; it's stirred by the rise of its new, corrupted elements of harmony.