Nothing is more terrible than losing your soul without knowing it. Soul Deprivation is by far one of the more sinister ways that magic can cause great harm to a being very essences. Unlike selling ones soul to a demon in order get what you want you are still connected to your soul to keep turning into a monster. The transformation into such a creature pain and torment should never be able to walk the earth to begin with let alone walk among us.
Transmission & Vectors
The condition itself is not at at all contagious. Magic is the only way that condition can be acquired.
Soul deprivation is only caused when a individual's soul is taken from the unwillingly from them. This can only be done through dark magic or a magic item able to steal a soul.
Symptoms may very per individual to the body reacting differently the lack of a soul creating unique mutations only for that body, but the feeling of feeling empty inside is common. But mental symptoms develop the same over time, paranoia, madness, rage and bloodlust are some the many thing that the individual will show. It is unknown is these mutations are indefinite or not.
The only possible way that this can ever be treated is for the soul to be returned to its host as soon as possible before the body starts the reject the soul to the mutation that it is going through.This could also kill them in the process especially after later stages show. Trying to retrieve the soul can be very difficult in some cases. If the soul trapped in a item it is more likely you will be able to retrieve it. But if not there may not be possible to get it back if it is released.
They will keep mutating over time and the individual in question will end up as homicidal killing machining that will kill anything to appease its hunger simply known as The Lost What makes this worse is that individual does not age or die naturally, along with near invulnerability to just about anything. Except for magic and holy weapons.
It will take some time for the soul to readjust itself back it the body, which will lead to sickness, feeling too weak to do anything, lost of appetite
Anyone can be affected by this condition.
Hosts & Carriers
It is not possible for the condition to spread and will only affect the individual in question.
Soul Deprivation can be easily stopped if you keep a magic barrier from allowing magic to harm you. this can be done by being magic oriented yourself or caring a magic item with you at all times.
This condition can happen anywhere in the world and should only happen if dark magic is involved.
There are no actual records of when this condition first started, but there are records of soul deprivation around the world. This has also been seen for thousands of years since then. Except for one major outbreak that happen 1500 years ago during the Night War. Which affected hundreds of people over several decades.
Very few people actually know about soul deprivation and know like about magic to begin with. Only those who are experience with magic or know about the effect of magic know about the condition. The affect individual seem to act normal until later stages where they will into hiding until they go on a killing spree while keeping a low profile of at the same time. People who actually see them will just think of them as monsters and try to kill them, failing in the process if they do not have the right requirements to do so.