Dweomer (pronounced "dway-oh-mer") is the fictional system of magic depicted in Katharine Kerr's novels of Deverry. This system is described by Kerr as being rooted primarily in nineteenth-century British Rosicrucianism. It also has some similarities to Theosophy.
While practitioners of dweomer, called dweomerworkers, do possess supernatural knowledge and abilities, the principal aim of dweomer is not acquisition of power, but personal enlightenment through harmony with the universe on all its planes. Dweomerworkers view themselves as servants of supernatural beings known as Great Ones, once-human spirits dedicated to the enlightenment of all beings. However, throughout the novels, numerous "dark" dweomerworkers have been encountered, who are chiefly concerned with acquiring personal power, and serve only themselves, not the Great Ones.
Kerr repeatedly (if subtly) emphasises throughout the Deverry novels that dweomer is not a replacement for science, and that dweomer knowledge does not provide the answers to a lot of questions about the world.
Physical: The physical plane is what most people would call "the real world." It is the "lowest" or "outermost" plane.
Etheric: Directly "above" or "within" the physical plane is the etheric. The substance of this plane is extremely malleable, able to be shaped by mental effort. On the lowest levels of this plane, one can see into (and sometimes interact with) the physical world. There are "tides" of elemental force on this plane, which shift in a regular pattern several times a day. Certain dweomer-workings must be renewed each time the elemental tide changes. Certain regions of the etheric plane may be associated with specific elements, though the novels are not clear on this point. The etheric plane is also the true home of the Wildfolk.
Astral: Directly "above" or "within" the etheric is the astral plane. Like the etheric, the astral plane can also be shaped mental effort. Other systems of magic refer to it as the Akashic Records, a sort of cosmic record of everything that ever happened.
The novels have briefly mentioned numerous other planes, including: the Orange Lands, the Green Lands, the Wildlands, and the Land of Husks and Rinds.
The gods themselves are in fact representations of higher-planar forces, which have been imbued with some degree of sentience by being worshiped. Both dweomer-workers and priests are able to tap these forces, though the dweomer-workers seem more adept at it. Deverrian priests are seldom shown channeling god-force; the only effect they seem able to achieve with it is divination. (Bardekian priests, on the other hand, seem to have knowledge and skills comparable to secular dweomer-workers.)
Secondsight: Dweomerworkers have the ability to see etheric forms and forces: manifested Wildfolk and other spirits such as haunts, a person's life-energy aura, or and constructs such as bodies of light and astral seals.
Dweomer-warning: Dweomerworkers often receive premonitions of danger, which is often described as a sensation of intense cold running down the back.
Command Wildfolk: The Wildfolk are the not-quite self-aware spirits representing the five elements: gnomes (earth), sylphs (air), salamanders (fire), undines (water), and sprites (aether or light). With the aid of these spirits, dweomerworkers can manipulate the elements, accomplishing such feats as instantly lighting a fire, creating light, and controlling the wind and weather.
Scrying: Scrying is the practice of viewing distant people, places, or things by magic. While looking into a focus of some sort-- often a fire or a pool of water-- a dweomerworker concentrates on what he or she wishes to see, receives a vision of it. However, in order to scry for something, the dweomerworker must first have seen it in the flesh. Large amounts of water have been shown to interfere with scrying, because of the powerful "curtains" of energy large masses of water emit. By scrying each other out, two dweomerworkers can form a mental link and communicate by a form of telepathy.
Spirit Projection: By creating a "body of light" as a vehicle for one's consciousness, a dweomerworker can travel on the higher planes. The body of light is joined to the physical body by a silver cord, which passes energy back and forth. Should the cord break, the dweomerworker will die.
Ensorcellment: To ensorcel a person is to produce an effect similar to hypnosis by manipulating the person's aura. Ensorcellment is much less easily resisted than hypnosis, and can produce much more pronounced effects than hypnosis. Some effects that can be produced by ensorcellment include: stunning or dazing an individual, altering a person's emotional state, causing someone to forget (or remember) certain things, planting subconscious instructions to be carried out at a later time, or controlling the individual by totally subsuming their will. Only a dark dweomerworker will ensorcel an individual without his or her explicit consent. (For those wondering why anyone would consent to this, the Deverry novels feature one example of an ensorcellment being to the benefit of the target, when a prince is given a pronounced stammer to help him hide from his enemies.)
Ritual Workings: A number of different ritual workings have been shown throughout the novels. One is the invocation of powerful spirits such as the Elemental Kings or the Great Ones for aid or advice. Another is the creation of an "astral seal," a barrier which blocks attempts at scrying for things within it, and prevents dweomerworkers from entering the warded area in a body of lpight.
Invisibility:' This spell doesn't make someone truly invisible; it just makes them hard to notice.
Enchantment: One of the least-often seen dweomer workings is that of placing an enchantment on an object. Such objects are very rare. Enchantments which have been discussed throughout the Deverry novels include a talisman of noble virtue known as the Great Stone of the West, an enchanted metal that glows when one of the Westfolk comes near it, and a silver ring which gave its wearer the ability to command the dragon Arzosah Sothy Lorezohaz.
Glamour: A glamour is a false seeming. It can make an object appear to be something else, or cause a person to appear more charismatic.
Binding of Spirits: Dark dweomerworkers have been shown binding Wildfolk in gemstones as a form of imprisonment, and to recently-dead corpses to create a sort of zombie servant. Dweomerworkers of the light will never bind one of the Wildfolk in this way without their consent. An example of this is the previously mentioned Great Stone of the West, which draws its powers from the spirits who inhabit it.
Shapeshifting: The dweomerworkers among the Westfolk know a working which allows them to transform themselves into animals, usually a bird. The working is extremely dangerous; if not done properly, it can kill the practitioner. The technique is described as an extension of the more common spirit-projection ability. The dweomerworker begins with an animal-shaped body of light, which is used as a "mold" for the substance of the phnysical body. Dweomerworkers who use this technique sometimes exhibit animal instincts while in animal form. This ability originated with the Westfolk, but some human dweomerworkers have also learnt it. Whether human or Westfolk, the dweomerworker has no control over the form they take - it is instead a reflection of his or her true self. In some cases, the form may not even be one known to the Dweomerworker (for example, the Westfolk dweomerworker Dallandra takes the form of a small bird, similar to a linnet, but which no one seems to recognize).
Retrocognition: The ability to see what occurred somewhere at a previous time.
A number of magical objects have been described throughout the novels. Some of them are:
Bronze Knife: Dallandra brought a crude-looking weapon to the physical plane from Evandar's realm. It has the ability to harm Guardians manifesting on the physical plane because it exists simulaneously on both planes. they Crystal Pyramids: A pair of truncated crystal pyramids, one white and one black, which when touched together, allow passage between Annwn and the world the ancestors of the Deverrians originally left.
Curse Tablet: A lead tablet with Marryn's name and a curse written on it. Nevyn was unable to disenchant it, so he placed it in a special container which sealed its power.
The Great Stone of the West: Nevyn created this talisman of the noble virtues to guide the conscience of Deverry's king. It is inhabited by spirits referred to as "planetary spirits," which can communicate with the Great Stone's possessor, who hears their words inside his or her head. From the way they interacted with Jill, they appear to have a rather coarse and snarky manner.
Rose Ring: This finger ring, made of dwarven silver is engraved with roses on the outside, and with Elvish sylabary characters on the inside, which read "Ar Zo Sa Soth E Lor Ez O Haz." These characters spell out the name of a dragon, whom the ring's wearer can a comamand. It was enchanted by Evandar.
Silver Casket: Nevyn placed the curse tablet inside a box made of dwarven silver, and placed dweomer seals upon it, to contain the tablet's influence and prevent it from harming Marryn.
Silver Daggers: The daggers which all Deverrian mercenaries carry and which gives the band it's name, all have two dweomer workings placed upon them. The first creates a strong antipathy to the spiritual aura of the Elcyion Lacar. As a result, the metal will glow with dweomer light if there are any elves nearby. Dallandra believes that the daggers siphon life-energy from elves to generate the light, so that it would be dangerous for one of the Elcyion Lacar to handle or be near one of them for an extended period of time. In later books, it is revealed that the daggers are capable of causing injury directly to the etheric doubles of elves, resulting in wounds that do not heal.
The other spell causes the weapon to return to its "true owner" by a sequence of seeming coincidences if it is lost. However, because all the Deverrian smiths who know how to create the special alloy the daggers are made of were taught by the Dwarven smith Otho, all the silver daggers created in Deverry see Otho as their "true owner."