The Morrigan (also known as the Morrigu) was the shape-shifting Celtic Goddess of War, Fate and Death. She also presided over rivers, lakes and fresh water, in addition to being the patroness of revenge, night, magic, prophecy, priestesses and witches.
Her name is interpreted in various forms..."Great Queen," "Phantom Queen" or "Queen of Demons." She was said to hover over battlefields in the form of a raven or hooded crow and frequently foretold or influenced the outcome of the fray. The Morrigan was often depicted as a triune goddess whose other aspects were manifested in the Goddess Badb (meaning "Vulture" or "Venomous") and the Goddess Nemain (meaning "Frenzy" or "Fury"). The Morrigan was one of the Tuatha De Danaan ("People of the Goddess Danu") and she aided in the defeat of the Firbolgs at the First Battle of Magh Tuireadh and the Fomorii at the Second Battle of Mag Tured.
The Celts believed that, as they engaged in warfare, the Morrigan flew shrieking overhead in the form of a raven or carrion crow, summoning a host of slain soldiers to a macabre spectral bane. When the battle had ended, the warriors would leave the field until dawn in order that the Morrigan could claim the trophies of heads, euphemistically known as "the Morrigan's acorn crop."