Crom Cruach

Crom Cruach was the god of weather and fertility. Crom Cruach was not a Tuatha Dé Danann deity. A great gold idol was set up in Mag Sleact ("Plain of Adoration") in Ulster. Crom Cruach was a bloodthirsty god where human sacrifices were performed. The early Irish sacrificed their first-born child, praying for fair weather and good crops.

According to the Book of Leinster, the worship of Crom Cruach was said to have been started by Tigernmas, the Milesian high king of Ireland. One Samhain night, Tigernmas and a third of the worshippers were killed themselves in the bloody rites. St Patrick was said to have called upon Christ to destroy the idol.