The Sands of Argo
Argo is a harsh land. The air is toxic to most sentient beings, though wildlife has evolved and adapted to it. The sentient races adapted by learning to breath through the white sands common in the deserts of Corvus and Mahesh. The sand purifies the air and makes it breathable. They have also learned to burn an ore called malcocite that purifies the air in a much wider radius which allows the citizens in a town or city to go about their business normally.
It is said that the Bittering occurred nearly 1000 years ago, after the Cataclysm when a chasm opened to the underworld and was sealed at great cost by a band of warriors. Since then, the people of Argo have had to wear breathing apparati because of the air.
The continent of Corvus is currently made of two nations: Gildar and Andilor. Gildar has existed since before the Cataclysm. It is a nation of Humans, Elves, and Dwarves that look down on all the other races and have kept them as servants and slaves for centuries. The humans, elves, and dwarves are known collectively as khartoum, while the other races are called khargous. In 885ac, Khrall the Dragonborn led a revolt of the khargous against Gildar and carved out a region in the north of Corvus that became what is now known as Andilor.
Malcocite is mined in only one place in the world: The Palus Mines in the swamplands of the north. While there is no question that the Gildari forces would overwhelm the Andiloreans, the cost of life and the relative undesirability of the swamplands have maintained a tense peace between the nations, so long as Andilor continues to provide the malcocite at reasonable prices.
The continent of Grundiloc to the northwest is where the Cataclysm occurred. It was there that Argo was split and the hordes of the underdark began pouring out. Once the chasm was sealed, the continent went dark and has remained dormant for a millenium. There are rumors of adventurers setting out into the continent, but no first hand accounts exist.
As we enter this world, it is nearing the bicentennial anniversary of the founding of Andilor. Khrall still rules in the Andilor and is generally well liked by the people, though many wish that he would be harder on the Gildari people. Gildar no longer keeps the Khargous as slaves, but they are looked down upon throughout the land.