Beings born from the Darkness, evolved to be as closest to her as possible.

Demons are creatures whose primal instincts are violence and dominance, even before self-preservation. Due to this, there is a very low number of demon families.

There are exceptions, of course, some demons evolved to be smarter and more peaceful than primordial demons. These kinds of demons are more adept at magic and science.

Appearance.

Most demons look like humanoid dragons, quadripedal reptiles, arachnoids, cephalopods, and more. They are distinguished by their aura or unusual features compared to their Earthly counterparts.

An example of this are the Cerberi, the prideful and powerful three-headed hell hounds.

The main difference, besides their three heads, is the elemental powers that they possess.

Biology.

This section will focus only on the low and middle-class demons, from high-class to supreme-class the normal laws of nature bend and things like senescence suddenly stop.

Demons are, in their majority, carnivorous regardless of sharing the same physiology and often the same intelligence as their Earthly counterparts.

The biology of demons varies from one species to another. A cerberus doesn't have the same physiology as a roc.

Nonetheless, there are phenomenons that happen to every demon.

Soul consumption: Every demon can feed on souls and emotions, it's something that is innate and doesn't need to be taught. In the worst of cases, when food can not be found, this is the last resort.

Mutation: When a demon consumes too many souls, the spiritual energy absorbed begins to accumulate. Overflowing with energy, the cells are forced to adapt to contain such energy. These mutations vary from species to species.

Given enough time and energy, low-class demons can gradually transform into high-class demons.

Society.

There are few tribes, villages, and just two cities with a considerably civilized society; pretty much "human-like".

Low and mid-class demons bases their decisions on their primal instincts, they basically are (without any kind of discrimination or offense) animals. It's really difficult to find a large group of the same race of demons in the same continent.

High-class demons have the instinct to either be alone or rule over lower-class demons building their own "kingdom"; these kingdoms usually are the most civilized zones of Hell. These "lords" respect each other's territory and normally don't try to conquer it.

Supreme-class demons are super powerful beings with abilities and enough power to make any other demon fall to its knees and follow their commands. I haven't had the chance to be graced by their presence but legends say that the very Hell bends to their existence.

These gods care just for the ones they directly rule in their territory, which contains billions of stars and thousands of planets.

Every demon is ruled by the primal rule that governs the multiverses and it's as ancient as the creation itself: The strong survives, the weak perish.

Low-class demons will always kneel to mid-class demons, mid-class demons will kneel to high-class demons and high-class demons will kneel to Supreme-class demons.

Supreme-class demons can impose their authority over any lower demon they please and make it join their armies.

Classification

By now, you must be aware of the four classes. I'll try them explain in detail.

The classification of a demon is not selected by its specific abilities or intelligence, it is selected by the demon's raw power. A rank is something totally different and has nothing to do with classification.

Low-class: The weakest, their power is too weak or non-existent. They are tied to the laws of nature; they need to eat, drink and sleep. Their elemental and magical power is too weak and would only represent a threat to regular mortals.

Their intelligence is also pretty low and can be lured into traps easily.

Mundane weapons can harm them and even kill them without a problem.

Middle-class:These demons can be taken more seriously. At this point, they are beginning to use souls and spiritual energy as fuel instead of flesh and water; they are transcending the laws of nature. Their elemental and magical power is formidable and can be a threat to skilled warriors with magical knowledge.

They are sentient and intelligent, they can talk, read, and write. These demons are the ones that usually create pacts and deals.

Even when they are beginning to transcend their own primal biological needs, they can be harmed by refined weaponry and killed.

High-class:There is a huge gap between mid-class and high-class. These demons have transcended their biological needs and can feed on souls and spiritual energy if they please. Their elemental and magical power can rival that of a lesser deity.

For example, humanity has many deities. A high-class demon can be comparable to them.

Their intelligence is pretty high and if they used to make deals and pacts with mortals, they have perfected the art at this point.

Just powerful champions can aspire to defeat them.

Supreme-class: There are only nine demons that can be classified as such, these demons are of course our true gods. Since I haven't had the chance to speak directly with them, I can only write what is in the legends.

They have transcended time and space, they are almost one with Darkness. Their power is so great that they can devastate planets if they please, my grandfather told me that two of them fought once.

The Goddess Lilith, the most beautiful and captivating, mother of the succubi.

And the God Dahaka, the being made of pure Darkness, powerful and honorable, the one who created the sacred city that shares his name.

Their fight shook all of the dimensions and plains in Hell.

I just hope that this project of mine doesn't offend them.

Hybrids.

In extraordinary cases, demons can breed with other non-demon species giving as result the birth of hybrids.

They are a curious case until the date there's no explanation for their most interesting ability; Demon form transformation or simply Demon Form, which is the true form of these hybrids.

Hybrids often look just like their non-demon parent and their demon instincts of violence and dominance are heavily reduced but can appear in situations of life or death.

Although the demon genes are latent, they act passively influencing their biology and behavior. The influence is very little but powerful.

These hybrids are sensitive to the spiritual, can absorb souls, and have improved senses in comparison to normal members of their species. As half-demons, their bodies are stronger than that of regular mortals.

Either through training, stress, or being on the verge of death, hybrids unleash their true form and with it, all the suppressed or sealed demonic power. This transformation bends the surrounding reality and the body suffers accelerated mutation to adapt to the sudden liberated power.

After this, hybrids can seal their true form at will and return to look like any other member of their species.

Note: Hybrids have their own chapter, they will be explained in detail there.

The transcendentals.

These demons have turned into concepts like some of our gods, no longer have a physical body, or have become the embodiment of darkness. Many demons don't lose their bodies but develop the ability to travel through dimensions and universes.

The demon with this special ability if it's on the army of a high-class demon, it's given the rank of baron and it's assigned to find new worlds to conquer.

The demon that has this power is usually more than capable to bend reality, shapeshift, read minds, modify soulless matter, and more.

Relationships.

Demons are, pretty much, conquerors that desire to consume everything to Hell. Just exceptional cases are peaceful with human-like fauna or human themselves.

Between demons, there are some species that tolerate each other letting them get into their territory. Rocs and Cerberi are good examples of this.

Succubi usually are peaceful and are friendly, this doesn't mean that they are not lethal. If they are under attack, they will eliminate the threat without a second thought.

The souls that arrive in Hell and appear in their territory, are guided by the succubi so they can keep that soul from harm.

Note: Succubi also have their own chapter.

Demons that have kingdoms don't like their territory getting invaded or trespassed without their consent. While they try to have a peaceful solution, they won't hesitate to kill the disturber of their peace.

Demons hate Angels, the children of the Light.

There are exceptional cases where a demon and an angel don't fight to the death and even get to build a friendship. Scholars have found a memory sphere belonging to two legendary entities that confirm the aforementioned.

A primal demon born from the sin of Pride and an angel born from the virtue of Humility.

Eons ago, when Vyraj was divided into Heaven and Hell by the agreement between our 9 Gods of Darkness and the 9 Gods of Light, a powerful foe forced Demons and Angels to fight together against the said foe.

This foe is known as Voruteut, a race of beings whose goal is the destruction of the creation, in other words, their goal is the annihilation of every multiverse that exists and will exist.

After the war, while demons and angels departed to their respective universes, the angel born from Humility decided to stay in Hell with her friend.

The demon born from Pride and the angel born from Humility fell in love and their union created the first nephalem.

Types of demons

There are hundreds of demon species, due to this, I will just focus on the most famous and the ones that had expanded to other universes.

Cerberus: A three-headed hellhound, while normally they prefer to be alone, there are cerberi that create packs just like wolves. The regular size of a cerberus is around 5 to 10 meters, this hellhound possesses fangs and claws sharp enough to pierce solid stone and strong steel. They can develop elemental abilities turning them into a dangerous threat.

Roc:A demonic bird of prey, its titanic size makes it the natural predators (and sometimes prey) of Leviathans. They look like earthly eagles but have a distinguished lower mandible that separates in two. Just like cerberi, they can develop elemental powers that allow them to destroy continents.

Leviathan: An enormous sea serpent with a scaled body; unlike other demons, they feed on the natural energy of a planet due to the lack of prey and souls that their massive size originates. They have poisonous blood and, depending on the species, spit water at high speed, fire like a dragon, or acid.

It's unknown if our gods have something to do with it but Rocs and Leviathans always inhabit the same planet and just exist in pairs. They cannot have offspring and can live for an eon before succumbing to age.

I and my colleagues think that since they both feed on the energy of the planet, more than two rocs and two leviathans would turn the planet into a wasteland.

Dragon: One of the most powerful demon species. They mainly have two forms, one of them is quadrupedal and the other is limbless; there is more variety but these two are the most common.

Their size varies from one species to another, a green dragon's normal height is twelve meters while a black dragon can reach a titanic size.

The main weapons of a dragon are its fangs and claws sharp enough to pierce through armor effortlessly, a different kind of "breath" that can vary from fire to miasma, and its own armor, its hard scales that protect them from external attacks.

A limbless dragon can use constriction or use its body to hit.

Our gods sent them to other multiverses so they could thrive and sometimes prepare a planet for conquering.

Hell was inhabited by two powerful dragons once.

A red dragon of at least one hundred meters that transcended to personify the concept of dreaming, it was given the task to find a proper place outside Hell for demons to inhabit.

This dragon had many names but the most famous is Great Red.

The other dragon is the personification of infinity.

A black dragon of titanic size and unmatchable might for everyone who is not a supreme-class demon or the red dragon itself. It was given the same mission.

This dragon is known as Ouroboros.

Update: These two dragons had acquired their own chapter, I can't thank enough the wise Tiamat, she had graced us with her presence and knowledge.

The last type of demon receives the name of 7 sins also known as 7 hells.

7 Sins: Demons that are born from a soul that has enough desire to live again and compatibility with one of the sins. They begin like a low-class demon and can turn into a high-class demon just like a regular one.

This type of demon is (besides succubi) the one that looks more human-like. Although, it's not uncommon to find more animal-like sins.

They have a tendency to wield scythes, swords, spears, axes, or shields.

Even if they are low-class demons since they were reincarnated the intelligence of their last life remains along with the memories. The sins usually seek to look for a master to serve, the reason behind this is unknown for now.

Now, this chapter is concluded. More aspects of the demonic societies and history have their own section in this book.

If you have read until this point, I and my colleagues ask you to keep reading. If you are a demon or a half-blooded, you must read everything, this is a part of your culture regardless of your origin.