Demons

Demons are entities born from mana.

Counter Demons
The least diverse of the demon species. They are mana replicas of humans, however, they are not exact replicas, as they possess cat-like eyes, claws, and features such as eye color and hair color are different from their human counterparts. Such as, a white-haired human will have a black-haired counter demon. They result from the imbalance created by birth. When a human is born, especially the recent version of them, these manaless beings cause a drain of mana to be born. Counter demons are the result of the world's mana repairing itself, resulting in a replica of the human-shaped void in the world's mana. For this reason, a counter demon's lifespan is tied heavily to the life span of the human they were born from. When a human dies and becomes a spirit, the mana that was drained from their birth is restored, erasing the mana created clone. Witches/Warlocks do not drain the world's mana upon their birth, so they do not have counter demons. If a human or half-demon becomes a demon upon their death, the counter demon merges with their human half, resulting in a reborn demon.

Animals do not drain mana as heavily as humans do upon their birth, and since they have the ability to become demons naturally with age, they too lack counter demons.

Pure Demons
The most diverse of demons. they are the first lifeforms that appeared on Earth after the World Tree, Yggdrasil, crashed into the earth from space. As the world tree produced mana, giving life to the ancient world and ceasing the Earth's treacherous environment, demons began to manifest from the mana produced from the tree. Thanks to the world tree stabilizing the world, many years later, organic life forms that lack mana would emerge. It is unknown how demons were initially able to form from the mana produced from Yggdrasil, nor is it known if other world trees exist, or if other world trees can produce mana and demons. There are many kinds of demons that arose from the world tree, and demons born from living organisms that began to incorporate mana into themselves, turning them into demons.

Demon Species:
Goo Can't really be classified as a demon...Not quite slimes, as those are definitely demons. These entities are goo, of various colors. They were the 'first' demons, as they ARE the first entities born from mana. These entities latch onto living beings, killing them by infusing their mana filled bodies into the manaless organism they attach themselves too. They take over the organism's mind, in most cases, erasing it, preventing them from becoming a spirit or an independent demon, forcing the soul of the creature to fuse and be devoured by the Goo. However, instincts, and memories from the manaless organism are absorbed into the Goo's new form, making it behave more like an animal than it originally would. It is a horrific process, with flesh and bone melting, blood leaking out, and the Goo reforming the organism into a new or altered form. The Goo can continue to do this to several other organisms, even if it already has an altered form. It is said that when a new demon species is born, it is because these THINGS got attached to something they shouldn't. Descendants of the Goo make up modern pure demons. No one knows if the Goo still exists, and a lot of effort has been placed by the pure demons to make sure the Goo doesn't attach to anything else. If a Goo manages to attach itself to a half breed, the resulting demon would greatly resemble the demon form that individual would take on naturally.

Slimes Demons that are made up of slime. They are not like the Goo, but they can shapeshift and spread their body out thin. These demons prefer humid and densely vegetated areas like swamps, where they can sneak up on their prey. They are ambush predators, and their bodies are full of digestive enzymes, breaking down anything that manages to get caught in their bodies. Some like to disguise themselves as food and wait for something to eat it so the Slime can devour their organs from the inside out.

Original Dinosaurs These demons resemble stereotypical dinosaurs, large lizards with scales. In fact the first dinosaurs are demons that did give rise to many other demon species, while the more bird like and feathery dinosaurs gave rise to modern organisms (i.e. Scaley Velociraptor gave rise to similar demons, feathery Velociraptor gave rise to birdlike and organic descendants).

Dragons Well known descendants of flying original dinosaurs. Though not all of them hail from flying dinosaurs but water or land based ones.

Kitsune These demons can be born as Kitsune or age into Kitsune, as they originate from foxes that have matured to 100 years of age.

Nekomata

Hellhound

Crystals A demon whose true form is a crystal. The body that is used to interact with the world around it is made of light. Crystals can use their light-based body to shapeshift. The crystal is often buried within their light-based forms, making them difficult to defeat in the realm of the living.

Mimics A type of demon with the natural ability to shapeshift. While many may take on the form of a item, turning itself into a trap, many of them exist in other forms beyond chests, items, etc. Though that doesn't stop one from playfully chomping on anyone who does mistake them for a chest.

Reborn Demons
Demons born directly from humans. These human born demons were never spirits upon their death and became something else. It is rare for this to happen, with a 1% chance of it occurring. Demons born from witches and half-demons also make up this category. Though half-demons will greatly resemble their demon ancestor/parent, their strength does not determine their ability to change between demon and humanoid forms. Witches and warlocks on the other hand can have drastic changes to their forms, even if they are early enough in the bloodline to still have animal/demon-like features. Though a witch/warlock's eyes will be altered to be more demon/cat-like, their original eyes can still be seen through faintly (i.e. Comet, a witch who became a demon, has red eyes as a demon however he faint outline of a star and a comet can be seen in her eyes). Witches, half-demons and warlocks who become reborn demons have a great increase in their magical power, while humans who become reborn demons gain the ability to use magic.

Demon Species
Dual Livers A special kind of reborn demon. They are similar to zombies as they often return from 'the dead'. Their demon form is the same as their human form, however, any wounds obtained from dying remain (i.e. if a dual liver was shot in the head, their human form would lack the bullet wound, however, their demon form would have it, regardless if they died from it initially or that death occurred after being sent back to the demon realm). These demons are able to continue their human lives a while longer since they have the inability to age. Kenny McCormick from South Park would classify as a Dual Liver in the TSOAC universe, though his demon form would be horribly mangled.

Vampires A reborn demon that is very similar to a Dual Liver, however, they perished as a result of malnutrition. These demons are in a state of permanent malnutrition as a result and obtain their nutrition by consuming the blood of others. Consuming blood only satisfies them for so long before they need to consume more. While in the demon realm, they are unable to feel hunger since they lack a human body and exist in a 'spirit' like state. All vampires have fangs, however different subspecies of vampires may have bat-like features, claws, allergic reactions to garlic, sun sensitivity, etc. The subspecies of vampires are often determined by where in the world they died as a human. Those who die by the hands of a vampire are likely to become vampires themselves. This is not the same for Zombies. Kyonshi, Jiangshi, and western vampires are examples.

Wendigo A reborn demon that is similar to Vampires, however unlike Vampires, these demons have antlers and possibly deer-like features such as ears, tails, and possibly even hooves. A good portion of them are born from starvation instead of malnutrition. Wendigo needs to consume human flesh or very soft food (liquids they can consume however the more solid the food is, the more likely they can't stomach it), or else they run the risk of their body rejecting it, leading to them regurgitating it later. The reason they can hold down human flesh and even properly digest it is a result of human flesh having the correct and exact amount of nutrients a wendigo lacks in their own bodies, as well as strengthening their immune systems to disease. Unlike Vampires, a Wendigo's hunger persists even in the demon realm, making them go to the realm of the living to hunt humans.

Zombies A reborn demon when the body of the human is mostly intact. These demons normally have some sort of injury that impairs brain function or movement such as brain or nerve injury being the cause of their death. While there are zombies who lack brain or nerve injury, they are all in some state of decay that will impair body functions to some degree. Zombies do not spread like a virus, and they can die in the living realm by simply staying there too long, which can cause their forms to decay until they die, sending the zombie straight back to the demon realm. A zombie usually stops decaying in the demon realm, however, that is not always the case.

Skeleton A kind of reborn demon, where the human body of the demon has been destroyed to the point of being left as bones upon death, or to the point of organs and skin being unable to cling to the bones. These types of demons are likely to arise from things such as nuclear explosions, burning to death, melting from lava, being devoured by an organism, acid, and other methods that would leave only bones rather quickly. Some zombies can become skeletons if their body continues to decay after becoming a demon.