At the end of The Seventh Age the lands descended into chaos and total war. The Shadows, rulers of the Plane of Air, fostered the chaos in an effort to undo creation.
The Last Hero, with his allies, moved to stop the Shadows machinations. He was fooled and all but failed in his mission.
The Shadows almost succeeded in destroying the world. They destroyed most of it. What remains is a series of islands and desperate peoples. Trying to survive in a world where the Gods are busy just ensuring survival and the Shadows are trying to finish their work.
Welcome to the Eighth Age. The Age of The Shattered Lands.