Aravan

The world of Aravan is one deeply divided. The Northern Continent clings to its peace accords by a thread while the Southern Continent has gone silent, with no goods or news coming to or from the region. Meanwhile, the entire world braces for another Crossing.   Roughly every thirteen hundred years, the planets, the cosmic representation of the various planes, align. When this occurs, a Crossing takes place, and all of the planes collide. Demons, Devils, Celestial, Fey, Primordial beings, and others spill into the material plane, wrecking havoc across the world. When it ends, people, libraries, and entire cities are just gone and kingdom's which remain are left burning, frozen, or empty.   This is a DnD Campaign setting.