Being Tainted is the result of a spiritual fracture, which can occur when a soul suffers a trauma too great or has had their binding severed incorrectly.
The Tainted are a breeding ground for miasma, which causes hysteria, violent impulses, sexual impulses, illness, and, eventually, death.
However, the Tainted themselves generally do not die from miasma poisoning and can even thrive if they choose to succumb to it.
The Tainted are also referred to as being "Stained" which derives from a small soot-like stain that appears on their hands when they first become tainted.
Over time, the stain grows until it fully envelops the infected person.
At which point, they fully succumb to the Taint and can experience drastic changes in personality.
Miasma is a form of spiritual blood that emits from someone tainted. The toxic energy causes an illness simply called, miasma poisoning.
Miasma poisoning heightens the emotional state of the infected, including the Tainted themselves. It can cause hysteria, hallucinations, delirium, physical ailment, or psychosis.
Due to the fast spreading nature of miasma and its side effects, it became a wide-spread epidemic.
If not contained, it often kills hundreds and even thousands within a short span of time.
Areas that have lost their inability to contain the damage refer to this as the Plague. All infected parties and areas must be quarantined.