Children of the Forest

The Children of the Forest are a mysterious non-human race that were reportedly the original inhabitants of the continent of Westeros. Small, druidic, magical creatures, they were already living in Westeros 12,500 years before Robert's Rebellion when the First Men migrated to the continent.

According to legend they were last seen during the Andal invasion six thousand years before the War of the Five Kings. In the present day, most believe that they are simply the stuff of myth and never existed at all. Even the few that do believe they once existed, such as Maester Luwin or Ned Stark, believe that they have long since gone extinct.

Biology
The Children of the Forest were said to be humanoid, but when grown to manhood they were no taller than human children. They generally preferred to live in the depths of the forests in hidden villages, in crannogs of the swamps, or in caves. Thus they came to be known as "the Children of the Forest".

Culture
The Children of the Forest worshiped nature gods, the countless and nameless spirits of every tree, every rock, and every stream. Their religion devoted to the Old Gods of the Forest had no complex temples, but according to legend it was the Children that carved faces into the sacred Weirwood trees. These carved heart trees were the closest thing to a shrine in their religion.

The Children of the Forest weren't very technologically advanced, though they were very woodcrafty and had a great knowledge of the plants and animals of the forest. They hunted using bows made of weirwood and used blades made of Dragonglass.

The wise men of the Children of the Forest were known as "Greenseers", who are said to have wielded powerful magic.

Background
Legend holds that the Children of the Forest ruled Westeros for thousands of years before the arrival of the first humans on the continent twelve millenia ago. They inhabited the vast primeval forests which spanned most of Westeros before humans came and began cutting them down. According to legend, the Giants also inhabited Westeros at this time, and clashed periodically with the Children. Whatever history, wars, romances, or triumphs the Children may have had in the untold centuries that they inhabited Westeros, their stories have been forgotten.

Twelve thousand years ago, the First Men from the eastern continent of Essos migrated to Westeros by crossing a land bridge known as the Arm of Dorne. The First Men began cutting down the Children's forests, including the sacred weirwood trees, leading them into conflict with the Children. The two races fought a desperate series of wars for dominance for the next two thousand years, during which the Children of the Forest destroyed the Arm of Dorne and flooded the the Neck through the sorcery of their greenseers.

After two thousand years of violence, the Children of the forest and the First Men fought one another to a standstill. The two races agreed to peaceful coexistence and signed the Pact on the Isle of Faces in Gods Eye lake, granting the open lands to humanity and the forests to the Children.

The Pact lasted for two thousand years before the enigmatic White Walkers invaded from the uttermost north, bringing death and destruction to both races. The Children of the Forest allied with the First Men to drive back the White Walkers in the War for the Dawn eight thousand years ago. After the defeat of the Others, the Children, much-reduced in number, are said to have helped Bran the Builder raise the Wall.

The Children of the Forest never had a large population to begin with, and they took heavy losses in the struggle against the White Walkers, from which they never truly recovered. Over the following centuries they gradually declined throughout from Westeros, until they had all but disappeared by the time the Andals invaded Westeros. The handful that remained were hunted or driven off by the Andals. The handful of Children that survived the slaughter were said to have fled to the far north, Beyond the Wall. By the time that Aegon Targaryen conquered and united the Seven Kingdoms of Westeros three hundred years ago, there had been no contact with the Children of the Forest for thousands of years.

According to the knowledge of the maesters, the Children are either extinct, or never existed in the first place and are a purely mythical race. This is disputed by the people of the North, who hold that they inherited their worship of the Old Gods from the Children of the Forest, who were real and have long since departed the realms of men for reasons unknown.

Season 2
Maester Luwin tells Bran Stark that many people think that magical creatures like the Children of the Forest never existed at all. Luwin tells Bran that he thinks they may have once existed in ancient times, but that they have long since gone extinct: "the dragons are gone, the Giants are dead, and the Children of the Forest forgotten."

In the books
In the Song of Ice and Fire novels, legend holds that the Children of the Forest ruled Westeros for thousands of years before the arrival of the First Men from the eastern continent of Essos, some twelve millennia ago.

Within the first novel, A Game of Thrones, it is speculated by songsters in the North that the Children might survive north of the Wall, though simply because no one is entirely sure what exists in the uncharted forests beyond it. Nonetheless, the Children have not been sighted in thousands of years, either by the Night's Watch guarding the wall or even the Wildings that live immediately north of it.

According to myth, the Children were diminutive in stature and few in number compared to humans, but formidable in battle. Their greenseers wielded powerful magics and their wood dancers were skilled warriors. It is hinted that the enigmatic green priests of the Isle of Faces in the midst of Gods Eye know some of the secrets of the Children and their ways, and others (especially in the North) may know something of their ways.

Physical appearance
Author George R.R. Martin has repeatedly insisted that the Children of the Forest are not simply his version of Elves, because "Elves have been done to death". Descriptions of the Children of the Forest presented in the fifth book, A Dance with Dragons, stress this. While the Children are repeatedly described as "dark and beautiful" this is not in the same manner of Tolkien's Elves: the Children are described as being smaller than humans with nut-brown skin, large ears, and glowing gold eyes, slitted like a cat's. They also have 4 digit hands (3 fingers and a thumb) that end in small claws instead of primate fingernails. They interwove vines and flowers into their hair and clothing.

Artistic depictions of the Children of the Forest in the "Complete Guide to Westeros" Season 1 Blu Ray featurettes depict them as nothing like stereotypical "Elves" of Fantasy fiction. Instead they are depicted as being an aboriginal people, somewhat like Native Americans or other hunter-gatherer peoples, adorned with totems and tattoos.