Vi’Rok

The mountains form a ring around the Midnight Expanse, its elevation and foothills turning the expanse into a bowl. Many claim that the mountains were once covered in green forests, a jungle that was petrified many centuries ago into the obsidian glass it exists as now.
  The mountains themselves are made of obsidian pillars that rise in steep tiers rather than the inclines of natural mountains. Each pillar is covered in strange glass formations that bear an eerie resemblance to trees and foliage, spanning out in all directions like branches. These glass formations form into each other at all sides, forming a canopy that blocks out all by the strongest rays of the sun that manage to peirce through the translucent dark obsidian.
  This creates an effect similar to caves on the mountains, vast networks that can lead many to get lost if they manage to wander in.
  The obsidian has been eroded by strong forces to sharp edges, even the smallest ones are like needles underfoot. Footwear can protect against the small needles, but a single misstep could slice open a person’s foot with ease; a trip or fall could lead to serious injury or death if fallen upon the sharp end of a spike or brushed up against a vine that cuts like razor wire and breaks off in the wound. The peaks of these mountains reach miles into the skies, while the foothills reach a mile into the desert below. It is particularly tricky on the foothills, since the obsidian spikes blend near seamlessly into the black sands.

Magic of all types ineffective within the mountains, the obsidian canopies causing interference in conjuring magic from light or even blood. Summoned creatures may still linger, in a weakened state, but if they are dismissed then they cannot be recalled within the mountains’ boundaries. Chunks of obsidian removed from the mountains does not retain this quality, but remains sharper than any knife to the touch.

Not many creatures can survive living on the Vi’Rok mountains, where there is no vegetation to feed on, and water flows away from the mountains, toward the savannah, and even licking dew off the surfaces of the obsidian could lead to painful cuts.
  However, this inhospitable trait has made it ideal nesting grounds of flight-capable birds. The sharp spires are too dangerous for predators to climb, and the geography too rough for them to stay for long periods waiting for the occasional chick to fall from the nest. Birds can nest in the tangled pillars of glass, while flying to catch their meals in the desert. A few larger hawks and eagles have even been seen to bring large kills back to skewer on the obsidian branches, to feed off for days.