Devils

    Demonology is a catch-phrase which actually includes the study of all creatures native to what are commonly referred to at the "Lower Planes", namely, The Nine Hells, Ghenna, Hades, Tartarus, and the Abyss.  Dominant amongst these creatures, and found in most cases throughout the lower planes, are the creatures known as demons and devils.  Demons are creatures of chaotic evil, fundamentally native to the Abyss, and devils are lawful evil beings who generally originate from the Nine Hells. There are, of course, numerous other creatures native to the planes in between these two evil extremes, but in numbers, in influence, and in likelihood of being encountered outside their home planes, demons and devils are by far the most important.

      Demons and devils come in an almost endless array of forms, some hardly stronger than a bug and some the equivalent of deities.  All, however, share certain characteristics dictated by the nature of their extra-planar existence.  Differing planes quite literally have differing "laws of reality";  it is unnatural, not to mention often impossible, for a creature or being to exist in a place where "its rules" do not apply.  The laws of the Prime Material Plane are different enough from the Lower Planes to prevent these creatures from physically existing in our reality, and thus these beings are in fact incapable of traveling here.  What they are able to do, however, is travel to the Prime in a form known as an avatar. 

      An avatar is a magical manifestation of a being, a form defined by the creature's natural identity in its native reality but expressed in terms of the plane in which it manifests.  Its size, shape, abilities and powers all correspond to its inherent form and nature on its home plane, but they manifest themselves by the standards of reality where the being is (thus the same creature's avatar might vary on different planes).  The avatar is the creature in all practical terms -- the being itself feels and acts exactly as though it were physically present, and its actions are functionally "real" in every sense of the word.  It is not, however, truly the creature itself, and this subtle distinction has important implications. 

      Any demonic or devilish being, even if by nature entirely mundane in its natural reality, is by definition a "magical creature" once it assumes an avatar form.  As such, they are all responsive to specific magical powers and spells, both holy and arcane, relating to conjuration, summoning and dismissal, confinement, and control.  Equally, they cannot go where magic cannot function or exist, such as inside an anti-magic shell. Creatures of the lower planes also appear to be sensitive to holy magic of a diametrically opposed alignment -- and note here that "sensitive" does not always mean "vulnerable". 

      An avatar form gives the manifesting being a full set of senses and feelings, including the ability to feel physical pain, and the avatar can be affected by both physical and magical damage to the point of being destroyed;  however, a being in avatar form cannot be "killed" as we normally think of the term.  The destruction of an avatar form banishes the creature back to its natural realm -- possibly a bit the worse for wear -- but generally speaking back to its normal condition.  However, that creature will be unable to form an avatar (at least on the Plane from which it was banished) for a period of time relative to the creature's power, usually measured in years or longer.  Even moderate-strength creatures can be banished for decades, extremely powerful creatures even for centuries, which explains why creatures facing such a fate suddenly become so open to negotiation, or will even leave of their own accord. 

        Because an avatar represents a creature from a differing reality, the manner in which it interacts with its reality is occasionally unpredictable.  Avatars are often immune to various elements or substances which their natural environment may have hardened them to, but equally can be unusually affected by substances foreign to their natural environments.  Thus using fire against a devil is somewhat pointless, but silver, which does not naturally exist in the Nine Hells, is dangerous to them. Equally, the avatars of even moderately-powerful demons and devils are foreign enough to the Prime that even magic itself will occasionally malfunction or fail to affect them, notwithstanding the above-mentioned vulnerability to conjuration (etc.) magic.  Many such creatures possess at least a minimal degree of magic resistance to arcane power, sometimes even holy magic in the case of the most powerful creatures    

     As lawful beings, the evil of devils is more systematic and organized than demons.  Devils are all about deals and about power, and their currency is souls.  Their service is readily available to those that will pay their price, and a devil never fails either to pay or to collect its due.  Their natural evil makes them eternally dangerous to treat with, for while a devil will always obey the letter of a deal, it enjoys nothing more than perverting that meaning to its own benefit. 

     The Nine Planes of Hell are a strict hierarchy where all creatures have a place and a purpose, where free will and choice are forbidden and all labor to fulfill the will of the Great Dukes who rule each plane.  Yet within this seemingly unbreakable structure, there is ever tension;  for every devil, from the lowest to highest, is in constant competition with its fellows, both to maintain its own position and for the chance to usurp another higher in rank. Yet such is the nature of the place that very little change occurs, because the iron hand of control seldom slips.

     Unlike demons, devils are relatively predictable in powers and abilities;  also unlike demons, they are just as likely to use brains rather than brawn to solve their problems.  When manifesting on the Prime Material plane, devils have a number of common attributes (exception: Lemures).  All can see normally in complete darkness, whether natural or magical.  They have the natural ability to Detect and Analyze Magic, Detect Alignment, See Invisible, Create Darkness (radius varies), Create Fire, and Affect Normal Fires.  All devils can Cause Fear, as the spell;  the frequency and intensity of the effect strengthens as rank increases.  They can also shift between the Prime Material and Ethereal planes at will.  They have a natural form of telepathy which allows them to communicate with any speaking creature in that being's natural language.  In addition, major devils (Horned Devils, Ice Devils, Pit Fiends) can use Charm Person, Suggestion, Animate Dead, and Create Illusion, at least one and possibly several times per day.  Major devils can also teleport without error to any spot they can see or they know of, and are capable of carrying considerable weight while doing so.   

      Devils take no damage from fire or acid-based attacks, and only half damage from cold, lightning, and other elemental attacks.  They are particularly susceptible to and dislike holy water.  Devils are not affected by poison of any kind.  Devils of all types (except lemures) can only be harmed by magical weapons or by mundane weapons made of at least 50% pure silver.  All devils are magic resistant, with the strength varying by type.  They are completely resistant to sleep and to charm effects, and any kind of mind control magic used against them is likely to rebound against the user.

      Unlike demons, most devils are in theory susceptible to a cleric's turning power.  In practice, this is confined largely to the lower level devils and to very high level clerics.  Nonetheless, devils have a distinct aversion to holy items of good alignment or association, and to all such displays of power, regardless of the details of religion. 

      Most Devils have a varying ability to Summon other devils, a power it is believed they can generally exercise once per day.  It functions in a manner similar to a Monster Summoning Spell, except that (like the demonic Gate) it only has a certain percentage chance of succeeding, with that rate varying by type. 

     As Lemures are never found outside the planes of Hell itself, they are not listed or detailed on our list.