In Scottish Gaelic folklore, as well as Irish folklore and on the Isle of Man, the ciudach is a cave-dwelling spirit or monster. Originally he may have been giant. Ciudach appears in stories from Inverness and Roscommon in which he had an affair with Gráinne mac Airt, daughter of Cormac mac Airt, while she is on the run with Diarmait Ua Duibne.
- MacKillop, James. (2004). Dictionary of Celtic Mythology. New York: Oxford University Press, Inc.