Book of Mormon
Usually, Book of Mormon stories show the Nephites as the more righteous, industrious and peaceful people and the Lamanites as wicked, lazy and warlike. Wars happen all the time between the two groups. But, near the end of the book, the Nephites become more wicked than the Lamanites, and all the Nephites die in their last war, except for one named Moroni who was directed by God to bury the Book of Mormon in a hill so that Joseph Smith Jr. could find it.