War.
War never changes.
The end of the world occurred pretty much as we had predicted.
Too many humans, not enough space or resource to go around.
The details and reasons are trivial and pointless, the reasons, as always, purely human ones.
The earth was nearly wiped clean of life, a great cleansing, an atomic spark struck by human hands quickly raged out of control. Spears of nuclear fire rained from the skies; continents were swallowed in flames and fell beneath the boiling oceans.
Humanity was almost extinguished, their spirits becoming part of the background radiation that blanketed the earth. A quiet darkness fell over the planet, lasting many years.
Few survived the devastation. Some had been fortunate enough to reach safety, taking shelter in great underground Vaults.
When the great darkness passed, these vaults opened, and their inhabitants emerged to begin their lives again.
One of the northern tribes claims they are descendants from one such vault. They hold that their ancestor, one known as the Vault Dweller once saved the world from a great evil. According to the legend, this evil arose in the far south. It corrputed all it touched, twisting men inside, turning them into beasts.
Only through the bravery of this vault dweller, was the evil destroyed. But in so doing, he lost many of his friends and suffered greatly; sacrificing much of himself to save the world.
When at last he returned to the home he had fought so hard to protect, he was cast out. Exiled. In confronting that which they fear, he had become something else in their eyes, and no longer their champion.
Forsaken by his people, he strode into the wasteland. He traveled far to the north, till he came to the great canyons. There he founded a small village, Arroyo, where he lived out the rest of his years. And so for a generation since it's founding, Arroyo has lived in peace;i it's canyons sheltering it from the outside world. This home; your home.
But the scars from the war have not yet healed, and the earth has not forgotten.