Since time immemorial, mankind has been haunted by the spectre of the unknown. In the wilderness stalk dangerous beasts, from the sky come the unfathomable forces of nature, at night the darkness swallows everything. These forbidden zones have one thing in common: the presence of Magic.
Magic corrupts the wildernesses beyond the edges civilization; a dark legacy of the Sorcerer's Wars nearly two thousand years ago. In recent times, these frontiers have been pushed ever farther backwards in accordance to the Hegemony's growth. The majority of scholars attribute this to the efforts of the Hero's Guild and the clergy to cleanse the land, some believe expansion is mankind's destiny and the Divine Architect is paving the way, while a few radicals suggest that modern society's over-reliance on magic is depleting the ambient magical energy of the world.
In a magically-saturated area, reality itself is as ephemeral as a dream. Any sense of permanency is lost as what may be in one's vision one moment may vanish the instant one's head is turned, or what did not previously exist suddenly appears.
Living entities which emerge from this chaos, invading more stable environs, are usually called monsters.
The term "Monster" is rather ambiguous, and its rise into common use is attributed to mankind's collective lack of interest in the abnormal beyond determining if it is a threat. What most people consider to be "monsters" are known as "magical beasts" by the academic community. They are living creatures, just like any other, but with a higher magical resonance than usual.
As even domestic beasts have some resonance with magic, the exact threshold of when a beast could be considered "magical" is hotly contested. In fact, as a highly successful magical beast usually integrates into the normal biosphere, most academic authorities believe that all life originated in this way: the Theory of Echaorum. However, most religious folk take issue with the notion that all life as we know it spontaneously formed from the void, refusing to let go of their dogma, which states that the current reality is the result of the long-term cumulation of minor changes and iterative development.
The one thing that practically all such chaos spawn have in common is a particular affinity for the element of Darkness. Lacking such, they would possess no instinct to improve or preserve the self, and thus would not seek to exist in true reality. However, since they themselves are of a magical nature, they can never truly escape the chaos from which they were born.
Magical Beasts each drag a little bit Unreality with them. This fact has lead to a major schism in opinions. The Church's Orthodoxy states that Chaos is accounted for in the Grand Design and is thus officially neutral, but most Heterodox sects including the Idoloclasts believe them to be carriers of taint which must be expunged. The Old Ways describe magic as part of the natural balance of the universe, including monsters under that. The various Mages' Magisters' associations see magical creatures as curiosities to be conserved and/or studied. The Heroes' Guild offers bounties only for varieties known to be dangerous, and, of course, the Abquaestors and Prefects care little for anything unrelated to revenue.
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However, not all beings borne of chaos possess a physical nature.
A Spirit is in many ways a monster's opposite. Where a magical beast must fulfill its needs to perpetuate its existence, a spirit has no needs to begin with. Therefore, instead of a Dark element driving the desire for self-improvement, all known spirits possess a Light attribute predisposing them to interact with others. It is hypothesized that non Light-aligned spirits exist, but simply never touch the world as we know it.
Spirits are alien and mysterious intellects: very little is known about them, even in this modern era of learning. Most act according simple patterns that strain the definition of the word "sentience", and even those which appear to possess an ego usually have "one-dimensional" personalities. Many philosophers question whether a spirit is even capable of changing its mindset: with no physical nature to provide continuity, doing so would be in every way identical to destroying the original and creating an entirely new spirit in its place.
Spirits have a curious tendency to "imprint" themselves according to human concepts, the classic examples being a wayward spirit cast into the role of a primitive tribe's deity, or a deceased loved one's spectre. This pattern has been the root cause of nearly all religious strife throughout history.
Some theologians maintain that as alien a being as a spirit cannot possibly empathize with humans, and thus even the seemingly benevolent examples are merely idly amusing themselves, and don't actually care about people; others believe that such 'imprinted spirits' actually are what they appear to be - a remnant of human souls given new life.
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Whatever the truth, it remains a fact that wild spirits can be as harmful to mankind as any natural disaster, so every major religion today practices some form of control or guidance for them. Even in the most remote villages, one can usually find some sort of good luck charm or household shrine designed to ward off or placate mischievous spirits.
Although a spirit has no physical presence per se, the ones with the most tangible effects on reality are focused around a specific object or location. The true purpose behind these foci is poorly understood, but it is useful when attempting to categorize a single spirit, or at least a collective or lineage of spirits with consistent behavior. Spirits with a narrowly-defined focus are far more likely to exhibit a comprehensible will than those without.
Spirits can manipulate the magical power of the environment, especially near to their focus, in order to produce tangible effects on reality. This could be as subtle as changing the weather, or as blatant as puppeteering a man's body. With enough power, they can even spawn servants in the form of monsters known as "Lesser Daemons", often called imps, sprites, elves, or goblins.
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The term "Daemon" has been used for too many things, and daemons in general have long had an undeservedly poor reputation due to the demonkin and devils that served the Dark Lords in millennia past.
Terms which have been used to refer to a subset of daemons in the past include 'fey', 'dragon', 'angel', 'archon', 'harpy', 'gargoyle', 'siren', 'djinn', and witch. The wide range of connotations for each of these terms will hopefully serve to demonstrate how inaccurate the public stereotype of daemons is, and how difficult formulating a precise definition is.
In truth, daemons are a race like any other, even if they are rarely counted among the races of men. The difficulty in classifying them lies in their volatility of form.
A daemon can shift its shape about as easily as a human might change their mood, political alignment, or demeanor. That is to say, some individuals can undergo drastic shifts at the drop of a hat, but meaningful change happens only slowly. One's form might change involuntarily, while another might be able to skillfully adapt their outward appearance like a human might mask their true feelings.
Practical research involving daemons has been forbidden by the church, on pain of death, but a few things are still known about their society. They prefer to live in the most magic-saturated areas of the world, either solitarily or in small groups. Group members typically are of the same gender, and align along both ideological and morphological lines.
Individuals tend to have a 'primary' form, usually humanoid but with exotic features such as wings, horns, tails, feathers, scales, etcetera. However, those which greedily seek to empower themselves often lose this form, adopting a more 'wyrm-like' one as befits their obsession.
A daemon almost never leaves its domain and enters the realm of mortals unless it desires something that magic cannot provide. An enduring yet erroneous myth that circulates around the Hero's Guild tells of the "succubus" or "nymph" seeking to reproduce with 'worthy' men... The so-called Heroes who repeat such drivel should bear in mind that there are far more tales out there of daemon seductresses who yank out one of their victims' vital organs and eat it in front of them, then feed the leftover meat to their next target.
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"So, I guess at least now we know what kind of being you are, Kat." {Others like Kat? Scary...} Arc couldn't help but chuckle, having more than one Kat exist would be pretty scary. "Well, I don't think we need to worry about it. From the sound of it, you're an extremely rare specimen."
But Arc was worried: not for Kat though, but for himself and the other minions. Did they classify as 'magical creatures' or daemons? (The 'Lesser' kind? Would that make the kind described by the book the 'Greater' kind?) The distinction between those two was never really made clear. Did that imply it was common knowledge, something everyone should already know? Or was the original reason forgotten knowledge, something nobody knew?
Or maybe, the author was just lazy.