Morrigan - Celtic goddess of fire, water, magick, death, and the moon, weaver of Fate. Often associated interchangably with the demigoddess-priestess Morgaine le Fey. Her most common symbol is the raven, into which she shapeshifts when the moon is full or dark. She presides over Avalon, the realm of dreams and magick. Invoke in spells for psychic power, transformation, banishing, protection, intuition, divination, and dream magick.
A word to the wise: they are not your servants, whores, or playthings. You do not "Keep" them. Treat them with respect, and you shall be rewarded. Fail to do so, and they shall respond accordingly.