Essentials of Demonology

Demons are the remnants of immoral human beings whose souls became separated from their lower bodies due to the intensity of their desires. Similar to the preta or "hungry ghost", a demon seeks to attach to a living person in order to parasitically gratify perversions through them. However, demons are far more dangerous than pretas since hungry ghosts are still possessed of a soul connection to deity. The predatory persecutions of a demon will know no moral limits whatsoever - these beings will remain until their bodies disintegrate entirely.

Demonic Nature
A demon is a desire body without a soul, lacking creative power and also any trace of the higher mental bodies. For this reason these beings are godless and cannot be redeemed. Rather, they are a material residue with no essential nature. Demons usually inhabit the astral plane, unable to manifest a material body for themselves and only able to cause aberrant thought, emotion and physical reaction within a victim.

Upon the astral plane, a demon is exposed to the full force of its inflamed and horrible desires, without a gross material body through which this force can be attenuated. Without hope of a salvation from its torment (and without even the inclination towards knowing what hopefulness is in the first instance), the being's automatic recourse is to obtain a physical body through which it can reduce its pain and temporarily avoid its disintegration into nothingness. It is thankfully a rare and powerful demon indeed which can form a material vessel for itself, and so most all specimens do the next best thing - they seek out a living person which they then attach to, infecting them with their own sick desires.

Soulless Men
A very rare occurrence is the phenomenon of the truly soulless individual - the apparently human remnants of a person who accumulates such an extreme degree of gross desire that part-way through life his soul returns to deity without the occurrence of his material death. When the soul departs in such a manner, the lower bodies are left behind, including the physical vessel itself which of course remains unchanged in appearance. This vessel is now a true demon - its higher mind and connection to deity lost forever, it will proceed to prey grievously upon those it can obtain as victims in horrendous ways until destroyed, without a trace of hesitation or remorse. This entity is not to be confused with the individual suffering from the condition of psychopathy brought about by full demonic possession, for whom, although difficult, moral reform is indeed possible.

The Eighteen Types of Demon
The expression of a demon's nature will depend upon the nature of the person from whom it was formed.
 * The Zombie - Spirits of the wrathful dead, invisible but known to possess corpses in order to kill.
 * The Mimic - Spirits of deceivers, these shape-changing beings imitate the dead and the living.
 * The Spectre - Remnants of those who gave into murderous terror, they haunt the living.
 * The Savage - Mutant humanoids who embody without a soul and seek rapacious destruction.
 * The Vampire - Spirits of rampant egoists which seek to drain the vitality of the living.
 * The Bodach - Spirits of those who feared predation in life, known to stalk and torment victims.
 * The Wisp - The remnants of once-living sadists, they thrive upon the infliction of pain.
 * The Wraith - The hateful traces of those consumed with spite, seeking to inflict death upon others.
 * The Ghoul - Spirits of cannibals and those who gorged upon flesh, they consume the living.
 * The Giant - Spirits of tyrants and those overcome with rage, they crush and brutalise all they can.
 * The Succubus - Seductive spirits of the vengefully heartbroken, they possess anyone they can.
 * The Mania - Spirits of insanity and deranged thought, known to warp reality and inflict madness.
 * The Fury - Spirits of those who were violent radicals in life, seeking to lay waste to order.
 * The Aberration - The bizarre remnants of the malignant and misplaced, propagating degeneration.
 * The Reaver - Spirits of havoc and mayhem created from hysterics and rampant marauders.
 * The Fiend - Slaughterous spirits formed from mortals who in life sowed violence and bloodshed.
 * The Plague - Spirits of suffering and ill health, responsible for the spread of disease amongst mortals.
 * The Devil - Spirits of existential nihilism, all that remains of once-living heretics and sorcerers.