Sidhe

The Sidhe (shee) are rich in the folklore of the British Isle and for all intents and puproses they are faries, such as the bansidhe (banshee). In Merlin the Sidhe are the immortal race of Avalon, the Island of Youth and they appear as small blue humanoid winged creatures. They are magicians, Gaius describes them as masters of Enchantment and a cruel race of beings.

The series has not yet at least explored these creatures in detail, but when we meet them they have banished Aulfric and Sophia from Avalon giving them human bodies and a mortal existance. However This does not seem to have much effect on their magical power, as Aufric can still cast bolts of deadly magic and summon the Sidhe to him.