The Irish word for fairy is sheehogue [sidheóg], a diminutive of “shee” in banshee. Fairies are deenee shee [daoine sidhe] (fairy people).
Who are they? “Fallen angels who were not good enough to be saved, nor bad enough to be lost,” say the peasantry. “The gods of the earth,” says the Book of Armagh. “The gods of pagan Ireland,” say the Irish antiquarians, “the Tuatha De Danān, who, when no longer worshipped and fed with offerings, dwindled away in the popular imagination, and now are only a few spans high.”
And they will tell you, in proof, that the names of fairy chiefs are the names of old Danān heroes, and the places where they especially gather together, Danān burying-places, and that the Tuath De Danān used also to be called the slooa-shee [sheagh sidhe] (the fairy host), or Marcra shee (the fairy cavalcade).
On the other hand, there is much evidence to prove them fallen angels. Witness the nature of the creatures, their caprice, their way of being good to the good and evil to the evil, having every charm but conscience—consistency. Beings so quickly offended that you must not speak much about them at all, and never call them anything but the “gentry,” or else daoine maithe, which in English means good people, yet so easily pleased, they will do their best to keep misfortune away from you, if you leave a little milk for them on the window-sill over night. On the whole, the popular belief tells us most about them, telling us how they fell, and yet were not lost, because their evil was wholly without malice.
Are they “the gods of the earth?” Perhaps! Many poets, and all mystic and occult writers, in all ages and countries, have declared that behind the visible are chains on chains of conscious beings, who are not of heaven but of the earth, who have no inherent form but change according to their whim, or the mind that sees them. You cannot lift your hand without influencing and being influenced by hoards. The visible world is merely their skin. In dreams we go amongst them, and play with them, and combat with them. They are, perhaps, human souls in the crucible—these creatures of whim.
WB Yeats