Fomoire, in Irish myth, a race of demonic beings who posed a threat to the inhabitants of Ireland until they were defeated by the god-race, the Tuatha Dé Danann. The name Fomoire may mean “demons from below (the sea),” and their leader Balor had one huge deadly eye. The most important of the gods, Lugh (see Lugus), is the offspring of the marriage of a god, Cian, and the daughter of the monstrous Balor, and it is stated that originally the gods and the Fomoire were allies.