Pixie

"Pixies are the servants of the Sidhe."

- Gaius to Merlin Pixies are faerie-like creatures and the loyal servants of the Sidhe.

Appearance
They have pink skin, large pointed ears, long noses, dozens of long black warts on their face and plump clawed fingers. They also have long, purple tongues which they used to eat flies in a manner similar to frogs. Their appearance varies from the traditional pixies of the myth.

History
Pixies are the servants of the Sidhe. One Pixie, Grunhilda, served the Sidhe elder and, disguised as a human, became the nanny of the daughter of Lord Godwyn, Princess Elena, so she could be turned into a Sidhe queen. At the age of 20, Elena was arranged to be married to Arthur Pendragon. Merlin discovered the Sidhe's plot and Grunhilda informed the elder who tried to kill Merlin in his sleep but died trying. As Gaius gave Elena a tonic to release the Sidhe out of her, Merlin attacked Grunhilda with his Sidhe staff, and killed her, turning her into a pile of Pixie dust (The Changeling).

Abilities
Pixies are able to disguise themselves as humans. They are also capable of mildly powerful magic, and quite high resilience to an offensive use of it. In fact, Merlin, who was able to kill a Sidhe with only one blast from his staff, had to hit Grunhilda several times to kill her.

Pixies have a certain knowledge of Sidhe magic, and can cast mildly powerful Sidhe spells (in the show, Sidhe spells are in Old Irish).

They can also create Pixie dust, which apparently helps with Changelings. When destroyed, their corpses are reduced to Pixie dust.