Lord Zack's Planescape
Azeroth is a world on a plane that is both familiar and strange to the inhabitants of worlds like Oerth and Toril. Many familiar races exist, but in forms that are strange and altered from the perspective of inhabitants of other worlds. It has a history of conflict between it’s inhabitants and the “demons” (in fact consisting of once mortal creatures twisted by “fel energy”) of the Burning Legion and it’s recent past has been dominated by this conflict. Due to the influence of the Legion, Azeroth has experienced an influx of immigrants from the world of Draenor, which until it’s recent destruction, was a far distant sphere on the same plane.
It’s inhabitants have a different view of the greater planes, most notably knowing the Ethereal Plane as the Twisting Nether.