Wikipedia
Cermait
In Irish mythology, Cermait (modern spelling: Cearmaid) of the Tuatha Dé Danann was a son of the Dagda. He was known by the epithet Milbél ( honey-mouth. See also Ogma). He was killed by Lugh after he had an affair with Lug's wife. The Dagda cried tears of blood for his son. Cermait's three sons, Mac Cuill, Mac Cecht and Mac Gréine, avenged his death, and went on to become joint High Kings of Ireland.