The Shifting Isles

It is a pretty old world. Untold ages ago, the people of Hyperborea were not yet what they were supposed to be. They spent their lifes running from an all consuming enemy - something they just called the "Darkness".
It was only when four heroes arose and claimed divinity for themselves, remaking their peoples in their own image, that they gained a fighting chance. These ancestral gods gave the people what they needed and managed to turn the tide of battle, from fleeing to fighting.
Since these days millenia have passed, minor gods have risen, others have fallen again. Following in their footsteps, empires rose and fell. Mortal life continued as you might imagine, until the very real danger of the Darkness became nothing more than a myth and a legend, something that has no real bearing on the world anymore. Their troubles now come from other places.
This last millenia has been a particularly troublesome one. Each major region was, or still is, plagued by powerful forces. The Southern Reaches lost the guiding voice that gave their rulers the power they so desperately craved. Nobody knows why or how the Dragon Emperor died, everyone has their own theory and scholars cannot agree on a thing.

The resulting instability was used by the self proclaimed Empress of Death, who used the strange necromantic energies of the Middlelands to raise an undead army to subjugate the Free Cities, only to be beaten by the combined desperation of her vassals.
All the while the Northern Realms had been clashing and warring with each other, eventually culminating in the Long War. The most recent of these catastrophes. From this war a new northern Empire emerged, establishing itself as a central power.
Within all this, a rumour has been spreading. A royal fleet, sent by said Empire has apparently found a second continent, by the name of Gondwana, filled with unknown creatures and plants, ruins of long gone civilizations, suffused by arcane magic far different from anything known to modern arcanists - but without a single inhabitant or any sign of them in sight.