The Tuatha De’ Danann are a basic part of Irish/Celtic lore. This race of divine beings was thought to comprise the fifth invasion of Ireland (according the the Book of Invasions…if one strictly adheres to the tenets of that book there were seven invasions but two were really part of one invasion so I decided to ignore those).
All these Gods and Goddesses were thought to have sprung from Danu. Danu sprang forth from the tree of life in the form of a river and gave form to various other Devine beings. There are also those who believe that Danu is not the Goddess referred to because Danu was not an Irish Goddess. These scholars suggest that Danann has to do with great artistic ability…thus a Goddess of great artistic ability. Regardless, this race of Devine beings, which were eventually displaced by others but never totally vanquished, had various powers and influences. We will a few of these Devine beings briefly. For a more detailed discussion of these issues, see Steve Blamires book “Magic of the Celtic Otherworld”. There are many Gods and Goddesses in this group so I’ll restrict my comments to just a few (more extensive coverage of the group can be found in “Celtic Myths” by Miranda Jane Green).
There were three craft Gods: Goibhniu, a smithy; Luchta, a wright; and Creidhne, a goldsmith. Together they made magical weapons used to defend the gods. Their weapons always flew true and straight and always killed.
One of these Gods was Lugh. He was God of light and associated with the long days of summer. A summer festival, Lughnasad, was held in his honor each year (still is). Lugh’s role was of considerable consequence. He was a Warrior God and helped the Twatha De’ Danann immensely in times of conflict. In fact, Lugh assumed leadership of the Tuatha De’ Danann because Nuadu, the original leader, grew tired of constant conflict and withdrew. During his tenure, Nuadu lost an arm in battle and had to relinquish power until a new silver arm was constructed. After reassuming his leadership role, the conflict continued and he finally turned the job over to Lugh, the shining one.