The Blue Men of the Minch
Folklore tells of a tribe of supernatural sea creatures called the Blue Men of the Minch, who used to inhabit the stretch of water known as the Minch, between Lewis, the Shiant Islands and Long Island.
They were humanoid in appearance with blue skin, kinned with mermen they would swim alongside ships passing the Sound of Shiant in an attempt to lure sailors into the water, and conjure storms to wreck ships. They lived in deep underwater caves in a clan system ruled over by a chief. Like many supernatural creatures they could be beaten with a cunning tongue, and by making sure you got the last word in a rhyme. Many a sea captain is said to have escaped sure disaster with the sharpness of his tongue, and his skill in riddles.
There are a few theories about their origins, it has been suggested that they were fallen angels, and on a more historical note, a folk memory of Moorish slaves marooned in Ireland in the 9th Century by Viking pirates and slave traders.