The Sidhe

[aeon]

The Sidhe (shee) are considered to be a distinct race, quite separate from human
beings yet who have had much contact with mortals over the centuries,
and there are many documented testimonies to this. Belief in this race of
beings who have powers beyond those of men to move quickly through the air
and change their shape at will once played a huge part in the lives of people living
in rural Ireland and Scotland.

http://celticsociety.freeservers.com/sidhe.html

http://www.sacred-texts.com/neu/celt/ali/ali222.htm