The Tuatha de Danaan are not elves. Why are they under this category? :P -Suileach

Mythologically, the Tuatha de Danaan preceded the Milesians in the occupation of Ireland, and displaced the Firbolgs and Fomori.

They are said to have come from the north, from four cities of great learning - Falais, Gorias, Finias, and Murias. Beyond that, however, their original origin is unknown. Some have suggested they were travellers from another planet or from a heavenly realm, as they're said to have arrived from the air, in a cloud of mist, and their skills - magical and otherwise - were advanced.

'Tuatha de Danaan' means, simply, 'The People of Danu'. Danu, or Dana, being their patron Goddess/Mother.

They are described as being 'gods but not gods'. They were a fierce, beautiful, strong, immortal people. They were renowned for their hospitality, their wisdom, and their skills in battle.

Many descriptions have them as tall beings, with red or gold hair, as opposed to the Fir Bolgs who were swarthy, small, and dark-haired.

After their defeat at the hands of the Sons of Mil, they are said to have retreated to the (or one of the) Otherworld(s) of Ireland. They used their powers of invisibility to become like spirits, but there are seers that claim they can still be seen on occasion - riding out of hollows or hills, or appearing as solitary, noble, beautiful women.