Every Immortal is immune to mortal illness, such as the flu or diseases. However, they have their own illnesses that are much more difficult to treat.
Soul Sickness is a disease of the Immortal population that occurs fairly often. It is comparable to a flu or a cold; easily treatable for the Immortal population, just incredibly annoying to deal with. If not properly cared for, it can become fatal for the Immortal.
On rare occasions, a human can come down with Soul Sickness as well, which is incredibly dangerous. If a human gets Soul Sickness, it is typically fatal within days.
Soul Sickness is caused by an overabundance of foreign energy within the soul. Typically, this happens to Immortals while they are fighting each other with soul-damaging attacks. A soul becomes damaged through exposure to energy that is a different wavelength/color than its own. The Soul is able to filter out small amounts of foreign energy without much trouble, but when there is an excessive amount of foreign, hostile energy, the Soul cannot filter out the energy properly. This then causes the Soul to create something similar to an immune response, in which it tries to destroy the excess energy. However, in order to do so, the Soul ends up attacking its own energy as well, which creates an effect similar to sickness.
The symptoms of Soul Sickness vary depending on if the afflicted is human or immortal.
Typical symptoms include:
Sluggishness/Lack of Energy
Soul-Colored ooze on wings
“Bloodshot” eyes with soul color instead of blood
Color draining from the skin
Color draining from the eyes
Inability to expel energy at all
Typical symptoms include:
Coughing up pus-like energy
Oozing pus-like energy from orifices
Sudden lacerations expelling pus-like energy
Treatment for Soul Sickness is rather straightforward as long as extreme symptoms do not manifest, and the afflicted is not human.
An Immortal can treat their Soul Sickness by cleaning their wings thoroughly and meticulously once or twice a day. By cleaning their wings, the Immortal manually removes the offending energy, and thus aids their soul in the filtration process. As long as they follow this routine, the sickness typically clears up in a few days to a week, depending on the amount of exposure to foreign energy in the first place.
If the severe symptoms manifest, the typical self-treatment will not be effective. It merely prolongs the suffering, though will keep the Immortal technically stable. Once severe symptoms appear, only a Virtue Class Angel or a Witch specializing in Constructive magic will be able to cure the Sickness.
This is also the case with humans. However, humans do not have any way to manifest their soul, meaning they cannot self-care. The only way for a human to receive treatment is a Virtue or a Witch. If the severe symptoms appear, only a Virtue will be able to properly help the mortal victim. A Witch will be able to stabilize them, but only a Virtue can truly cure them.
If a Virtue treats the sickness, likely the symptoms will alleviate immediately, though this depends on the exact wording of what the Virtue requests.
If a Witch treats the sickness, it typically takes a week from the initial treatment for the sickness to clear up. Occasionally, multiple sessions of Constructive magic are required in order to heal more severe cases.
A common mistake in the treatment of mortals in general is the bandaging of lacerations when severe symptoms appear. These lacerations, while deadly enough by themselves, are still allowing the foreign energy to dispel through them. If the wounds are covered, the energy will fester within the wound and bloat the soul. If left like this for too long, the mortal will act much like a surging Maculari or Pecus and unleash a mass amount of energy, shattering their soul in the process. This has only been recorded twice in written history.
The mortality rate for Soul Sickness is relatively low among Immortals, but much higher for humans. Only about 1 in 100,000 Immortals that contract Soul Sickness end up shattering because of it.
Humans, on the other hand, while they have fewer cases of Soul Sickness, have a much higher mortality rate of 1 in 100. Typically, a guardian angel will recognize the symptoms in their charge and will request a Virtue to treat the human without the human even knowing. However, younger guardians and the inattentive may not notice the symptoms, leading to the death of the human.
Demi-Immortals can also become afflicted with Soul Sickness, however, as long as they are not a Semi-Immortal or lower and have access to energy crystals, they can self-care just as an Immortal.
A Semi-Immortal or lower must be treated as if they were a human, though their symptoms will follow the Immortal symptom list rather than the human symptoms. This tends to cause late diagnosis, as many Semi-Immortals and lower are able to blend in perfectly with human society, and thus the symptoms may be associated with a possession instead of sickness.