Túatha Dé Danann – Origin

https://mariannetierney.com/2017/04/13/tuatha-de-danann-origin/

 The Túatha Dé Danann, the ‘People of the Gods of Danand’, by their association with pagan deities, have excited and inspired Irish folklore for generations. Their legacy has found its way into popular culture through the medium of film; (Hellboy II: The Golden Army) in online role-playing games; (Scion Companion) and books of fantasy fiction, (The Hobbit, The Lord of the Rings). Within the Lebor Gabála Érenn (Book of the Taking of Ireland) they are numbered as the fourth group who migrated to and occupied Ireland, succeeding the tribe known as the Fir Bolg.
Beginning with the chronological order of the LGE texts, as edited and translated by R.A.S. MacAlister (1870-1950), their origin is given as follows;

NEMED: R2 (267) Others say, (the Tuatha De Danann,) that they were of the seed of Beothach son of “Iardanaines” that is of the people of Nemed belonging to the party who went to the east to seek the maiden*: for they captured her, and made a great feast in the east, till their grandchildren and great-grandchildren came afterwards, (at the end of a long time).

(268) Others say that the Tuatha De Danann were demons of a different order, and that it is they who came from heaven along with the expulsion by which Lucifer and his demons came from heaven; having taken an airy body upon themselves to destroy and to tempt the seed of Adam. That is the fortress against which those who made that attempt advanced, in the train of the devil and his followers. So those people go in currents of wind. They go under seas, they go in wolf-shapes, and they go to fools and they go to the powerful. Thence comes it that this is the nature of all of them, to be followers of the devil. No genealogy of those people goes back; nor are they recognised as men of the world in general; and all that multitude broke out against the righteousness of the Sons of Mil and against the people of the faith of Christ.