Darkness

And so darkness became just another natural order of the world. Nothing unusual, and if you found it that way then perhaps you were the unusual one.

Almost like a fog, darkness and shadow creep into areas of civilisation, and a mother warns her children to take their daylight trinkets with them as they go out to play.

Manifestation

Darkness is just that: darkness. It is omnipresent and constantly surrounds the world to the point of all written history stating that the world has forever been in darkness.
It seems to be an arcane darkness, with magical properties but cannot be banished through any anti-magic means. If anything, it appears to be a naturally occurring arcane darkness.
Darkness becomes dangerous when it is more concentrated, and absolute absences of light excels the concentration. Shadows on their own don't tend to be dangerous, and are difficult to avoid. A general rule in most societies is at least a small light in every room.

Type

Metaphysical, Arcane