How about this:
Thousands of years ago, there were 3 warrior-kings, each did unspeakable things to maintain their land, power and wealth. When a great wizard visited the island nation, broken into 3 parts, he was offered residence in each one... each king wishing to attain the great wizard's power for his own land. But when the wise wizard refused, he was threatened by each king... After many years living is solitude, the wizard was approached by the 3 sons of the 3 kings. Each wished not to claim his power, but his head. The battle was ferocious, but the wizard ultimately won... he killed the sons, and cursed the kings, now they were separated by more than name. As the years have gone by, the 3 kingdoms have vanished, but it's said there are cults gathering, looking for the great-great-great-great-great-great-great-great-great-great-great-great-great-great-great-great-grandchildren of the cursed kings, who will once again rule the lands.
Demigods... they used to live among us, but have all since left... except 3, or so the story goes. One of land, one of sea, and one of air (or any 3 distinguishing factors), the 3 demigods were a source of spiritual leadership, of peace... but one day they vanished... their wives, husbands, children all remained, but they were gone... Each side blamed the others. 'Your sin was too great!' they would claim, but no one knew for sure. A war broke out, the land was divided, and the fighting was bloody, brutal, and merciless... Of course this was many a-year ago, and no one knows just what happened to the demigods... though they say their children still walk this land.