Ioris - The Underworld of Iolex

A brief history of Ioris:

While the surface world of Iolex went through the Calamity, Ioris, the lands under the continent, went through their own versions of the Calamity. The planar energies seeping into Ioris mirror largely those on the surface, though there is also some "seepage" or contamination from the Elemental Planes into Ioris' underworld expanses.   One of the key differences between Iolex and Ioris is the absence of Planestorms in the underground regions, instead replaced with a more even permeation of the rampant energies on the surface. And while one would be correct in assuming that the absence of Planestorms would have made survival easier in the underground realm, a significant proportion of its populations still perished during the Calamity - primarily as a result of geological change or collapse in the vast subterranean caverns.   Prior to the Calamity, Ioris shared a number of similarities with the Orvian Vaults of Golarion: they were nation or continent-sized caverns, potentially filled with a full array of biomes or only a few, some with false suns or stars set into their roofs. Some of these caverns instead took the form of seemingly endless oceans, or deserts. Needless to say, the Calamity changed all of that. The geological changes brought about during the Calamity destroyed nearly everything that had been carefully wrought, and altered all else. In some of the caverns, the false suns and stars fell from the ceilings, to sizzle and flicker fitfully in the cratered ruins left behind. In others, the seas drained into their neighbouring caverns, drowning the civilisations and lands that had previously thrived there, and leaving the previous ocean floor as stark salted deserts.   Despite all this, the peoples of Ioris had better initial survival rates than the peoples of the surface, though none of their civilisations or peoples emerged unchanged from the Calamity. Unfortunately, the monstrous denizens of the cavern depths - species like the Xulgath and the Gugs - were already better-adapted to survival in the dark or more resilient then their "more-civilised" neighbours, and large numbers of the surviving populations fell to invasion or predation.