Pneuma Flint of the Greylands
This obsidian-like material marks the razor edge of weapons and the soul traps among Greyland harvesters and hunters such as the Malok. Metal is rare enough in the Nexus to discourage it being used for armor or weapons, reserved instead for the specific needs of the Greylords. However, large deposits of this black rock are found frequently, hidden beneath the cracked, decaying dust of the Greylands, and are more than enough reason for mining operations to exist.
Rumor holds that this substance formed from the remains of dead gods, while others suggest that it is made of the tormented souls which were never able to move on and solidified under the weight of their regrets and emotions. It is often used in weaponry for its keen edge and ability to bolster necromantic powers. Larger fragments of pneuma flint are used in the creation of soul traps.
Pneuma Flint is part of the natural geology of the Greylands, and a hazard that most Eidolons just aren't prepared for, equivalent of wandering into an area of radioactive fallout; by the time you might notice, it is usually too late.
As disliked as the Greylords are, they're entirely necessary to the deities and entities seeking safe passage for their claimed souls through the nexus of planes.
