Children of Oberon
The Children of Oberon are one of the Three Races, and the most mysterious and magical. They are also known as "Oberon's Children", the Third Race (by the gargoyles), the Fair Folk (by the Scots), and the Dark Elves (by the Vikings). The lord of the race is Oberon himself, although they are not - for the most part - his biological children; the title refers rather to the fact that he rules over them as a sort of "pater familias".  Before Oberon rose to power, they were more commonly known as the Children of Mab. 
They are the origin of many of humanity's legends about faeries, elves, and other otherworldly beings, including even some of the gods of mythology.
Exactly when Oberon's Children came into existence is unknown, although they appeared some time after gargoyles and humans did. They were formed from magic, "evolving" from creatures such as the will-o-the-wisp, as was their home, the isle of Avalon. 
The earliest known ruler of these beings was Queen Mab, who was also the most powerful of them.  However, her son Oberon overthrew her (apparently somewhere in either the 5th or early 6th century A.D.) and took her place as ruler of the Third Race.  It was after his ascendancy that the race came to be known as the Children of Oberon rather than the Children of Mab. Compared to Mab, most of the Third Race views Oberon as a relatively good leader. 
Oberon's Children have spread throughout the world, and made themselves known to humans, who came to, (in many cases, such as those relating to Odin and Anubis), believe them to be gods and worshipped them. Even those who did not receive worship, such as Oberon and Titania themselves, found their way into human folklore and legend. At some point, however, Oberon passed a decree which magically forbade any of his race (including himself) from directly interfering in the affairs of mortals. This did not prevent them, however, from finding loopholes (something which even Oberon has done from time to time).
Despite this, many of the Third Race, including Titania, continued to hold a strong sense of contempt for mortals, and finally in 995, Titania committed some unspecified act that angered Oberon enough to banish all of the Fair Folk from Avalon, commanded to live in the mortal world until his anger passed. ("Ill Met By Moonlight") The Weird Sisters alone were left behind to guard Avalon from intruders, and even they were confined to a barge floating in the waters off its shore (they did not remain guardians for long, however, being soon expelled by the Magus when he and Princess Katharine came to Avalon). ("Avalon" Part One, "Avalon" Part Two)
The overall history of Oberon's Children during that time is unknown, although the activities of a few individuals have been recorded (such as the Weird Sisters' involving themselves in the affairs of Demona and Macbeth, Titania taking on the identity of Anastasia Renard, and Puck taking on the identity of Owen Burnett). ("City of Stone", "The Gathering" Part Two) Many of them, however, came to encounter Goliath and his companions on the Avalon World Tour (the details can be found in their individual entries). At last, in 1996, Oberon decided to return to Avalon and summon back the rest of the Third Race for the Gathering. All of them obeyed except for the Banshee (who had to be dragged back by the Weird Sisters), and Puck, (whom Oberon in the end condemned to remain in the human world as Owen Burnett). ("The Gathering" Part One) Currently, all of the Fair Folk except for Puck are on Avalon for the Gathering, although for how long is as yet unknown. The Gathering will continue for at least eight more Avalonian years, into 2198. 
The true existence of the Third Race is unknown to most humans, who, for the most part, believe them to be only mythical. Even in 2198, the general public will not be aware that Oberon's Children really do exist. 
Oberon's Children are beings of pure magic, not flesh and blood, although, as shape-shifters, they can assume human, gargoyle or animal bodies at will. Indeed, to speak of their biology is utterly inaccurate, since they have none as we understand it.  They may not even have any true forms, as we understand them, but merely forms that they assume more often than others. 
The Fair Folk are immortal, or at least, close to it.  None of them have died of old age as yet, although it is not an impossibility for the remote future.  They can be slain, but only with considerable difficulty.  Indeed, a Child of Oberon may appear to be slain, only to reappear later alive, as has already been the case for the Banshee and Anansi on the Avalon World Tour. ("The Hound of Ulster", "Mark of the Panther") Whether any of the Third Race have already perished permanently through battle is uncertain, although rumor has it that some of the Aesir branch of the Third Race, including Thor and Loki, were slain in a battle that became the original of Ragnarok in Norse mythology.  They are, more or less, an ageless race as well; they can take on any apparent age that they choose - as the Weird Sisters have already demonstrated - but it is only an apparent age.  They can even appear to look different to two or more observers at the same time, such as when Macbeth saw the Weird Sisters as three old human women at the same time Demona saw them as three ancient female gargoyles (it should also be noted that at that time they appeared in a third form, that of three young women in robes to observers of the scene). ("City of Stone" Part Three, "City of Stone" Part Four)
Oberon's Children use words to focus their magic when casting spells, with rhyming being particularly helpful (for anyone less powerful than Lord Oberon himself).  Nevertheless, they all possess strong magical abilities, although the exact nature of these varies from each individual to the next. There are "categories" among them, not only in terms of mythology (such as the Aesir and the Sidhe), but also in terms of function. Some of the Third Race, such as Anubis and Odin, are "death-gods", others, such as Puck, Raven, Anansi, and Coyote, are tricksters, and so on. This bent (the result of the Third Race being tied to the pure magic of the Earth) apparently determines much of an individual's precise abilities and modus operandi.  Thus, a "death-god" can bring about the death of a mortal life-form or even accelerate or reverse its aging processes, while a trickster will specialize in magical pranks. The preferred climate of the Child of Oberon in question seems to also serve as a factor; Odin, who primarily resides in Scandinavia when in the human world, can conjure up snowstorms and take on the form of a polar bear. ("Eye of the Storm", "The Gathering" Part One) It is possible that some Children of Oberon may have certain precognitive abilities, but likely with limitations. 
The Third Race do sleep and are capable of dreaming, though not as much as mortals do. They also do require food for energy, but what Oberon's Children would consider to be food is unknown at this time. 
The Third Race have at least one great shared vulnerability: wrought (or "cold") iron.  Their magic cannot affect it directly, and a Child of Oberon bound by iron chains is powerless to escape them unless released by someone else.  Such fates have befallen Puck and the Weird Sisters in the series; Coyote was likewise rendered a prisoner when trapped inside Coyote 4.0, who was made from iron melted down from the Cauldron of Life. ("The Mirror", "Avalon" Part Three, "Cloud Fathers") A Child of Oberon wounded by iron, as Oberon was by Petros Xanatos's harpoon, will wither and age dramatically, and the sound of an iron bell can incapacitate a Child of Oberon and even, if prolonged, kill him or her. ("The Gathering" Part Two, "Ill Met By Moonlight")
As has been said before, the Third Race are natural shape-shifters, and can (apparently) take on any form that they please. While they are genuinely in a mortal body, however, (be it human, gargoyle, or animal), they are subject to all the restrictions of that form. Thus, Puck, while in Owen Burnett's body, can use no magic (except to change back into Puck). There is a consolation in that, coincidentally enough, a member of the Third Race will not be weakened by iron when they have taken the form of a mortal (though most Children would still prefer to avoid it). 
While in mortal form, the Fair Folk can mate with mortals of the species whose form they have taken, and even have children by them. These "halfling" offspring often inherit a certain measure of their Third Race parent's nature, although this varies from individual to individual. Merlin, the halfling son of Oberon, was one of the greatest wizards of all time, while Fox, the halfling daughter of Titania, has virtually no Third Race magic in her due to her having been raised strictly as a human (only using her powers once, under uttermost stress, to strike out at Oberon when he attempted to kidnap Alexander). ("The Gathering" Part Two) Most unusual of halflings are the New Olympians, although they are another story, discussed more properly in their own entry.
Oberon's Children are governed through a sort of feudal system; indeed, their own feudalism may have become the inspiration for European feudalism. Oberon rules over the rest of the Fair Folk. The more powerful figures of the Third Race, such as Odin, serve as his vassals, and each one in turn has lesser Children of Oberon beneath him, such as the other Aesir under Odin. But ultimately, all of the Children are subject to Oberon. 
For the most part, Third Race society seems to be relatively informal. While on Avalon, they engage in various activities, including small battles (such as that between Odin and the Banshee), love-making, and contests of various sorts. 
The attitudes of Oberon's Children towards mortals vary. Some, such as the Weird Sisters, Raven, Anansi, and the Banshee treat them poorly, viewing them with scorn or contempt, often behaving as if humans and gargoyles were only playthings or nuisances. Others have been more benevolent or at least indifferent, such as Grandmother, Coyote, the Lady of the Lake, and Anubis. Oberon himself fluctuates; he decreed that the Third Race was not to directly interfere in the lives of mortals, but will bend that law himself if he sees fit (as in kidnapping Alexander). While the majority of Oberon's Children may indeed fall more into the "scornful" than the "helpful" element, it would be inaccurate and misleading to place them all in one category.
Oberon's Children have Avalon for their primary home, but many of them have local residences in the outside world, such as Asgard for Odin and the other Aesir. 
Known Children of Oberon
- Green Knight
- Lady of the Lake
- Queen Mab
- Morgana le Fay
- Sleipnir (note: Sleipnir may only be a hybrid of a Child of Oberon and a mortal horse)
- The Weird Sisters
Real World Background
The Children of Oberon in Gargoyles have two primary inspirations: the faerie-folk, and the various deities and spirits revered in religions around the world.
The fae are a mythical race of considerable prominence in British and European folklore and legend. While their representations vary from story to story, some features remain consistent about them. The faeries are said to look more or less like humans, but are possessed with great magical abilities; they are also immortal (although, so the stories go, they are also soulless, and when the world comes to an end, they will simply cease to exist).
The faerie-folk seem to have originated in part from whittled-down versions of the old Celtic gods, reduced in rank once the Welsh and Irish were converted to Christianity, and in part (some scholars believe) from dim memories of the Bronze Age people who lived in Britain and Ireland before the coming of the Celts, who feared the iron weapons of their deposers (the former "origin theory" fits in well with the notion in Gargoyles that the gods of mythology, such as Odin, were members of the Third Race). In legend, they are usually located in some sort of "faerie world," sometimes identified as a remote enchanted isle (such as Avalon in the series), though on other occasions as lying beneath the hollow hills (which fits in with the Banshee's residence in Cu Chullain's burial mound in "The Hound of Ulster").
Faeries were feared by humans, and believed to be dangerous to them. Legend claims that, when angered, they could strike humans and animals alike with illness, blight the crops, and send all manner of misfortune upon one; they were also said to kidnap human children and replace them with their own young as changelings. But they could also aid or bless humans, if they chose. As per the series, cold iron was indeed believed to be a strong defense against the faerie-folk.
Similar legends of faerie-like creatures are found in cultures all over the world, from the Americas to the Pacific Islands, and on every inhabited continent.
More information on the mythical roots of Oberon's Children can be found in the entries on the individual members of this species in Gargoyles.