Caoránach
In Irish folklore, Caoránach was a monster which was banished by St Patrick to Lough Derg. Perceived as female, Caoránach was said to be the mother of demons and devils.
Lough Derg ('red lake')was named for the blood of the dragon Caoranach issuing from an old witch's thigh bone, the dragon was slain by Fionn Mac Cumhaill.
In Irish folklore, there is a story of a she-beast that St. Patrick banished to Lough Derg (Red Lake). There is an island in the middle of Lough Derg that is called St. Patrick's Purgatory; it is said that the she-beast called Caoranach was sent to this island. It was said that there was a woman who followed St. Patrick very closely, but no one ever knew her name. After St. Patrick stated that he had banished the she-beast, this woman was never seen again.