Tadg

A Danann druid. Tadg was the son of Nuada and the father of Muirenn (Muirne). The legends never mentioned it, but Tadg was probably also the father of the druidess Bodhmall, the nurse of Finn, and of Uirne who was the mother of Bran and Sceolang.

Tadg was a powerful druid and the chief adviser of Conn Cétchathach, high king of Ireland. Tadg objected to his daughter's marriage to a mortal, Cumhaill, captain of the Fianna and chieftain of Clan Baiscne. It was through his machinations that he persuaded Goll Mac Morna to challenge Cumhaill for the leadership of the Fianna.

Tadg used his sorcery to cause fear and confusion among the Clan Baiscne. He also used his magic to seriously weaken and hamper Cumhaill during the captain's fight against Goll.

When Cumhaill was killed in the clan war however, Muirenn was already pregnant with their son. His wife fled and hid in Slieve Bloom, and gave birth to Demna (Finn Mac Cumhaill).