Ciudach

A cave-dwelling spirit in Scottish Gaelic folklore also known on the Isle of Man and in parts of Ireland. Initially the character may have been a kind of admirable giant; in stories recorded as far apart as Roscommon and Inverness, Gráinne has an affair with Ciudach while she is on the run with Diarmait. In later stories the Ciudach is a cave-haunting monster. See also CUGHTAGH.