Who is the father of the Tuatha Dé Danann?

There is this reference in Wikipedia:

The Tuatha Dé Danann were descended from Nemed, leader of a previous wave of inhabitants of Ireland.

The somewhat disjoint genealogies in Lebor Gabála Érenn (also here) can be pieced together to show

Nemed -> Iarbonel -> Bethach -> Ibath -> Baath

The Nemedians were washed off of Ireland by a tidal wave raised by the Fomorians; some of the survivors

Ibath and his son Baath went into the north of the world

Baath -> Enda -> Tavarn -> Tat-> Aldui -> Ordam -> Etarlam -> Echtach -> Nuadu Airgetlam

Well after the disaster the Fir Bolg resettled Ireland. But then the Tuatha De Danann returned from the north and at the first battle of Mag Tuired

The pleasant Tuatha De Danann brought spears with them in their hands: With them Eochu was slain, by the seed of Nemed of strong judgement. Yet the Tuatha De Danann suffered great loss in the battle, and they left the king on the field, with his arm cut from him; the leeches were seven years healing him.

Later

Nuadu Airgetlam was king over the Tuatha De Danann for seven years before their coming into Ireland, until his arm was hewn from him in the first battle of Mag Tuired.