Forces of Darkness: Demons
Demons are a race of magical beings motivated by Evil. They seek out to kill innocents and the forces of Good. Devils are generally regarded as the adversaries of the gods, while the image of demons ranges from mischief makers to powerful destructive forces. In many religions, devils and demons stand on the opposite side of the cosmic balance from gods and angels. Although devils and demons have been pictured in many different ways, they are usually associated with darkness, danger, violence, and death. Demons are unable to feel emotions and possess no soul or conscience. Almost all demons are immortal, and in some occasions, however, a demon can become good and desire to live a mortal life.
Most demons live in the Hell, Underworld, the mortal world or other plane of existence, depending on what goal they wish to achieve or how they influence the mortal world. When exiled, a demon is not allowed to live in or enter the Underworld which is punishable by death.
In most mythologies and religions, a devil is a leader or ruler among evil spirits, a being who acts in direct opposition to the gods. The general view is that devils are trying to destroy humans, to tempt them into sinning, or to turn them against their gods. Monotheistic religions often speak of one Devil, just as they recognize one God.
Devils and gods may be opposites, but they are also usually linked in some way. Many religious and mythological explanations say that the devils are related to the gods or that they are gods of evil. The gods of evil are result of losing to the popular or rival gods or religion.
A demon (sometimes spelled daemon) is generally thought to be a harmful or evil spirit or supernatural being, sometimes a god or the offspring of a god. Demons may be the messengers, attendants, or servants of the Devil. They are often monstrous in appearance, combining the features of different animals or of animals and humans.
Demons were not always regarded as evil. The ancient Greeks spoke of a person's daemon as his or her personal spirit, guardian angel, or soul. In many cultures, demons were merely inhuman supernatural powers that could be evil or good at various times, depending on whether their actions harmed or helped people.
Demons are said to come in every shape and form. And while that is true, most demons seem to have a human appearance, either by nature or with magical help. It is also possible for demon to have an amorphous body instead of physical form.
Hell Demons: The "Actual" demons, as in the ones that are born from all the Hate and all evil in Hell, along with the Dark Fallen Angels.
Dimensional Demons: Beings that inhabit different dimensions or planes of existence. They could have dark intentions or be born out of spite, vile, and evil. These demons usually have an ethereal existence or a not very solid composition in our plane of reality and the physical.
Earth's Demons: Beings that inhabit the Earth.
A Deal with the Devil
Christians of the Middle Ages and afterward believed that humans occasionally made bargains with the Devil, selling their souls to him in exchange for riches, power, or other benefits they would enjoy before they died. Witches were said to have made such bargains, an act that condemned them to death in the eyes of the church. An obscure German schoolmaster-turned-magician named Faust, who lived in the 1500s, gave rise to one of the most famous stories about a deal with the Devil. The legend of Dr. Faustus has been the subject of many plays, books, and operas.