It is all written down in Scottish lore
How she leaves the ocean for the shore
To lure a seaman to his ultimate fate
Or marry him and secure her mate
Soon she'll tire of the land-dwelling life
She'll have no desire to be anyone's wife
So she'll slip away back into the ocean
Never mindful of a mother's devotion
But her children grow, as all kids do
Tending to the sea of majestic blue
Males become captains in terrific tales
Their boats infamous beneath their sails
~ Morrigan Aoife
(pronounced kee-ask) * (although some pronounce it cask)
Known in Scottish Gaelic as maighdean na tuinne ("maid of the wave") or maighdean mhara ("maid of the sea").
This mermaid-type creature found in Scottish mythology is described as having the upper torso of a beautiful young woman and the lower portion or tail of a grilse (a salmon).
The Ceasg inhabits the lakes and waterways of the Scottish highlands. Similar to the lore of Mermaids and Sirens, which are found in many other cultures throughout the world, contact with this super natural creature many be perilous. They have been known to seduce sailors and lure them into the sea, presumably drowning them. However if quoted specifically the tales say only that "the sailors never returned home."
The best defense against a Ceasg or mermaid is to simply ignore them and quietly leave the area. However if one should approach, in the very least show them respect. Do not look them in the eye or listen to their song and do not go with them should they ask.
If captured the Ceasg has the ability to grant three wishes in exchange for her release, after which she will disappear. She can only be overcome by the destruction of her soul, which according to Scottish folklore was kept safely somewhere else in a super-secret place outside of her body, such as in an object or land feature.
Ceasg are curious about humanity. They are known to carry on love affairs with human males and can take human form in order to marry a mortal. Unfortunately the marriage usually does not last. The call of the water is too strong and eventually the Ceasg will return to her watery domain. The male offspring of a Ceasg and a mortal are believed to grow to be excellent sailors.
** One report said the Ceasg swallows lured sailors whole, however the writer was quick to point out that the thought was utterly ridicules since Ceasg have half-woman and half-grilse attributes meaning that she has a "human-sized" mouth.