The Fairies are beings that come in a variety of forms.
- Dark Fairies
- Flying Monkeys
- Goblins (mentioned by dean)
- Good Fairies
- Selkies (non canon)
- Trolls (mentioned by dean)
- Witches of Oz
Changelings appeared in the episode The Kids Are Alright; this is was first unofficial appearance of the Fairies.
They first officially appeared as the ''monster of the week'' in the episode Clap Your Hands If You Believe, where sam and dean was search for Ufo sightings. There are many theory about them one of the theories was they were fairies however sam and dean choice to ignore it and sam insult the woman who tells them this.
They also appear in the episode LARP and the Real Girl as well as in Slumber Party.
After Sam and Dean learn and believe they are dealing with the Fairies they search the lore about them some says they come in many forms and some are magical and mischievous being from the other realm this realm is considered another dimension, a diffrent reality.
Fairies, despite having different types, have some form of society and justice system called the Fairy Tribunal. This court decides on the fate of being that break the presumably existing laws of their kind. Fairies, despite being different kinds, all seem to cooperate with each other.
Humans can interact with them and ask for favors. Fairies can eat and drink like humans.
Fairies can make deals with humans, often exchanging their services, ability, power for a price.