Souls

“Perhaps the body was not a cage that held the soul, but a hand that gripped it like a cane, appearing to guide it, to command it, but all the while dependent upon it, gripping it all the tighter the more that it needed it, finally letting it go.”

― Christopher R. Beha, What Happened to Sophie Wilder

What a soul is isn't entirely clear... however, they are undoubtedly important. They are highly coveted, and what little is known about them shows them to be the key to many things. The one thing that souls have been proven to do is act as a conscience. Where pure souls can hear the "little voice inside," corrupted souls hear a corrupted version, while soulless beings hear nothing at all.

Types of Soul
There are three large categories of soul, each detailing key facts about how and if it exists. Apart from simply "human or inhuman," these classifications are the broadest possible.

Pure Souls
Despite the stigma, the idea of a "pure soul" does not come from action, age, gender, sexual status, or anything of the like. A pure soul, in its true definition, means a soul that is not corrupted by any magical force. A pure soul has not been changed in any magical nature, removed from one's body, or bargained with. Most beings on Earth have pure souls. Humans, Sirens, most bestial monsters, Selkies, and many more types of inhumans have pure souls. Upon death, their soul goes to Listr, unless claimed by an alternate force.

Corrupted Souls
Halfway between a pure soul and a lack of a soul is a corrupted souls. Corrupted souls exist, often (but not always) in the body of the person who they belong to, but have been touched by some influence that has altered them in some sort of way (usually negative), creating a skewed set of morals. Creatures such as vampires have corrupted souls. Upon death, their soul is healed and goes to Listr, unless claimed by an alternate force.

Soulless
Soulless beings have gotten rid of their soul in some way, be it through it being stolen, bought, or destroyed. Rarely, the soul never existed in the first place. Demons, banshees, half-demons, wights, strigoi, and many more monsters, especially the undead varieties, are soulless. Upon death, their soul is forfeit to whatever fate they surrendered it to. In some cases, it can be released and claimed by Listr.

Soul Corruption or Loss
For beings who corrupt or lose their soul, the method that is used to do such an act determines what kind of creature they become. While there is hardly an extensive list, there are some that are considerably more common than others.
 * Women who find themselves seduced by an undine and their soul stolen become banshees.
 * Humans who are killed by a vampire and agree to turn into one themselves find themselves as vampires with corrupted souls.
 * If a woman dies a violent water-based death, there is a roughly 1-in-20 chance that she will return as a rusalka, with a corrupted soul.
 * Those who sell their souls in exchange for something become demons.
 * Wights are formerly-pure souls who do so much evil that their soul decays, eventually disappearing entirely.
 * Strigoi are those who intentionally tried to modify their soul through magical means, usually to disastrous results.

Soul Effects
Those beings with a soul can experience certain things that soulless beings cannot. Beings with corrupted souls (such as vampires) are rather hit or miss on this list. Soul-exclusive things include, but are not limited to the following:
 * You must have a pure soul to be considered mortal. You must have a pure soul to be considered human.
 * Souls and conscience are the same thing... soulless beings have no inner voice to guide them (though may find a sort of artificial conscience through logic, interactions with friends, societal expectations, etc.). A corrupted soul usually still has this voice, but it tends to be skewed in some way.
 * A true soul is unable to be "killed" and even if the body dies, the soul will live on in Listr's realm if it isn't claimed by some alternate force.
 * Creatures with souls, and especially pure souls, are more adept at magic than soulless creatures. For some reason, this can be worked around if a person becomes adept before losing their soul... none of their ability seems to disappear, but subsequent things become harder to learn, taking more work. Many beings, especially demons, simply choose to find ways around this (keeping a "pet" witch, or buying magical talent, for example).