Irish, derived ultimatly from IE
Irish mother goddess, also called Anu (as in the Paps of Anu), or Dana, and called Don by the Welsh. Though the mother of the gods, and thus bestower of the name Tuatha de Dannan (People of Danu), she never appears in Ireland. It is thought that, like Boann and Sabrina, she is a river goddess, in this case the river which is named for her, the Danube, upon whose banks the Celts once lived.
Danu is thought to be the mother of the Dagda, and those who are sometimes said to be his brothers (other places called his sons), Nuada and Ogma. The confusion between brother and son may be an allusion to him fathering his own brothers upon Danu, as often occurs in mythology, but this cannot be certain, given the tendency of Irish monks to euhemerize their gods when writing.