Nekaset Decay

General

Nekaset Decay has only ever been found within the confines of Nekaset City, the Second Circle of Cericor.
It is a physically tangible manifestation of Scorched Radiation that takes on the appearance of black soot, that covers the exposed bedrock in a thin layer that is cold to the touch. While it has a slightly acidic reaction towards stone it is currently presumed to have no adverse effects against organic matter.  

— Excerpt from Great Sorrow Aftermaths.

From stone to air

One popular theory proposed that the soot actively transmutes the bedrock into a mixture of oxygen and carbon dioxide, that may irregularly tip more towards one end or the other. Something that may either cause spontaneous combustion of the air, or suffocation.  

— Excerpt from Great Sorrow Aftermaths.

Those Affected

There is another matter in regards to its effect on certain species and esoteric conditions. This is something that confuses researchers, as these instances deal with prospects that are, deep down, natural biological growths that merely take on certain aspects of inorganic properties.
Nekaset Decay appear to have harmful effects on the granite skeletons of Bosakere as well as the crystalline skeletons of Anishans. Those who are worst affected are the Vitralsha, due to their transmuted crystalline bodies.  

— Excerpt from Great Sorrow Aftermaths.

Hollow bones

While a few inhalations of the Nekaset Soot are not too harmful, it is the extended inhalation of the soot particles over long periods of time that holds the most risk. If an advanced stage is reached, then the afflicted will find themselves in a state where death may very well be preferable.
Anishans and Bosakere will find their bones being hollowed out and easily breakable until it reaches a point where their bones have effectively turned into air.  

— Excerpt from Great Sorrow Aftermaths.

Hollow bodies

Vitralsha suffer far worse:
Essentially, their entire bodies will slowly hollow out from the inside out, until eventually, their crystalline glass bodies have turned into nothing but air.
Due to their incredible durability that otherwise would make them immune to this sort of condition, the Vitralsha victims can survive for extended periods of agony until death finally greats them.  

— Excerpt from Great Sorrow Aftermaths.

Countermeasuers

The most effective countermeasure against this is to simply wear gasmasks every time one venture down to Nekaset City, or if that is not a viable option, then one should be sure not to stay in the presence of the soot for too long, and afterwards take long periods of time before revisiting it, allowing their Neiathi enhanced immune systems to combat the soot and break it down.  

— Excerpt from Great Sorrow Aftermaths.