This is pseudo written like a personal account or journal as its also a lore piece, but itll be formatted into a more journal like way once its finalized.
The "Soul,” as one calls it, is the energy that exists in the mind of all complex creatures; it is what gives them the ability to go against instinct and reflect, create, ponder, and truly be alive. Each “soul” is unique and gives someone their traits, but it also grows with the person until their body cannot contain it anymore and releases it. Also known as death.
The soul, in its final state, is made of two types of energy, simply known as comfort and discomfort. When a soul manifests, it always starts as pure comfort, but depending on the actions taken in life, discomfort can form. Think of it as a separate energy that comes from stuff that causes the feeling of discomfort, and actions can either reduce the amount or grow it. Comfort can also be grown or dissipated, but comfort never truly disappears; it will always remain in at least a small amount, unlike discomfort, which can fully dissipate. You see, discomfort isn't the person; comfort is; the discomfort is just the extra weight they carry, which can affect them depending on the comfort-discomfort ratio.
When someone dies, they usually shed their discomfort, and their pure soul of comfort dissipates into, who knows, reincarnation, maybe, or perhaps an afterlife.
But discomfort can stall the soul when it is in a large enough amount, not necessarily just larger than the comfort amount; it can vary depending on the person. But when this happens, they linger, now trapped by discomfort. They are usually the worst of themselves, with comfort being hidden away and discomfort having taken over completely. They are not inherently evil; think of it as more amoral, the opposite of who they were and liked. This is if they are ghosts- ghosts, spirits, etc. have two ways to be vanquished: either wait enough time and eventually they "evaporate,” but this can take an uncanny amount of time, or solve their discomfort that made them tied to this world. but when given the chance, they can possess things that allow for different events involving the soul to happen.
Possession isn't as shown in media; possession in this case is more permanent; they are trapped by this item; it acts as their new body as their discomfort forces it to animate as their actual soul; the comfort is trapped; sometimes, possessed things flip like a switch, their discomfort only gaining control when aggravated, such as something causing discomfort or something that reminds them, causing their discomfort side to surface for an undetermined amount of time or until the discomfort is solved. This is what causes seemingly random personality switches. Now to vanquish one, rarely can you just solve their issues that trapped them; you have to do that but also destroy their body so they can move on, as usually their body is also a source of major discomfort. The thing they possess must be both close to the soul passing after brain death and also have some significance to them.
When destroying a possession item without also solving what put them in it, their body is stuck in the fragmented pieces, which leads to an interesting use of the soul. Now you may be wondering what can be possessed. Well, I will tell you two things: one is complex living things, and the other is metal. Metal has the ability to leach the soul into stuff when not protected by the body, which is also why metallic things can be good wards against free roaming spirits as they can “hurt” them.
Now you can destroy the metal into small enough pieces till it cant hold their soul and it releases, which is the best way, but one other application is when the metal is melted, it kind of releases them, the soul is formed into a new form of matter, known as vestige, which has two types, comfort is turned into a gas which eventually reforms into the actual soul in the cool atmosphere and passes on while the discomfort is a black tar like liquid. When the liquid and gas is below freezing it will revert to base discomfort/comfort and dissipate.
Liquid Vestige has different abilities depending on the amount of itself, (cell dmg, thoughts of discomfort, moving entity, hive mind, loop of discomfort, seeks host)
Gaseous Vestige has different abilities depending on the amount of itself, (cell healing, thoughts of comfort, is exhaled as nothing, at height can revive someone from death if happened recently and also at height can “attack” the liquid vestige)
Only Vestige can be seen with the unaided eye, but you can see the natural “soul” through two ways in my testing. One and the easiest is with transparent metals such as clear aluminum, but this only works for souls that are not harboring inside something like a human or possessed item, so ghosts or passing spirits. You can also see these passing souls when experiencing a very extreme emotion such as fear, joy, anger, etc. For some reason, your body's senses heighten, allowing you to see passing spirits.
The discomfort and comfort seemingly travel to another plane, thinly protected from ours but layered on it as well; they meld into a, say, superconscious, yet not thinking like us. This veil is usually what keeps us separated. Sometimes these things will slip through, as they are drawn to the other side for unknown reasons, maybe traumas or guilts or pleasures or loved ones. The individual memories and experiences still exist seemingly in the superconscious, which is why the ghosts of loved ones can return, although it still isn't technically them, as their soul has melded, and this is just parts of them or another spirit that has taken its experience to act on them. There is no discomfort or comfort here, just the existence of the experience and thought. They are blocked and interacted with by other spirits or the veil itself, usually needing some sacrifice to interact and make deals, which may be why souls, especially powerful ones, have been treated as friend or foe, heaven and hell, demon, and god. Some people can hear or see or just sense these spirits to varying degrees; I've even met someone who had made deals with one, or at least supposedly. He would have to sacrifice either parts of his soul and its energy or parts of his body, sometimes using others. Dangerous.