This is stuff I'm working on for my anticipated 5e game. It's all subject to change without notice:
The land is laid out like a rough circle, and at its center is a city-state with crystalline spires, a Sapphire City grown from jewels that were alleged to be fragments of stars. The master of this city is not a king or emperor, but he does claims stewardship over all the land. He is famed as a wizard, and his greatest act of thaumaturgy was growing the Sapphire City. The Wizard seldom wastes his magic on such gaudy displays, though, and the more cynical speculate his primary art is something other than magic. All agree he is a man of cunning.
Four countries encircle the region of the Sapphire City. Their rulers are a contentious lot, but deference (or fear) of the Wizard holds them in check.
The country to the East is Yanth, and its colors are violet and yellow. It's ruler is a Clockwork Princess, at once wondrous artifact and great artificer, renowned across the land.
The country to the South is called Sang; Its color is crimson. It's ruler is the famed Princess of Battles, said to have hatched from an egg in a dragon's brood and to have vowed to take no lover who did not first best her in combat.
The country in the West is Virid, and green is its color. The Enchantress who rules it is said to be the most alluring woman in the world. She has a palace beneath the waters of an inland sea.
The country in the North is Noxia; Its colors are the black and gray of its blighted and gloomy landscape. Its dread Witch Queen cares little for the living and is obsessed with death--and undeath, and has been so since her lover fell into an eternal sleep.