The Nemedians (Muintir Neimhidh)

The third wave, who were ground down by Fomorian tribute and scattered to three corners of the world.

Neimheadh came from the Caspian Sea with a fleet of thirty four ships and lost all but one on the way. His people cleared twelve more plains and four lakes burst out of the ground in their time, continuing the pattern of each wave making more of the country habitable.

Their trouble is the Fomorians, who by this point are established as the opposition in every wave. The Nemedians beat them in several battles and then lost badly, and the terms imposed afterwards are the most quoted detail in the whole sequence: two thirds of the children born, two thirds of the corn and two thirds of the milk of Ireland, delivered every Samhain to Conand's tower on Tory Island.

They rose against it. They took the tower and killed Conand, and then Morc came with a Fomorian fleet and destroyed them so completely that thirty men were left alive out of the whole people.

Those thirty scattered in three directions, and this is the join that makes the sequence work. One group went north and their descendants came back as the Tuatha Dé Danann. One went to Greece and came back as the Fir Bholg. One went to Britain. Every wave that follows is therefore Nemedian blood returning to a country it had already lost once, which is a far more interesting idea than a simple series of invasions.