The Young King Of Easaidh Ruadh is a Scottish fairy tale collected by John Francis Campbell in his Popular Tales of the West Highlands, listing his informant as James Wilson, a blind fiddler, in Islay.
Andrew Lang included a variant in The Lilac Fairy Book, as "The King of the Waterfalls", listing his source West Highland Tales.
The young king of Easaidh Ruadh decided to amuse himself by playing a game with the Gruagach.
He did not take his advice to not go, but the Seanagal told him to ask for the prize, if he won, the cropped rough-skinned maid behind the door.
He went to play again, and his wife warned him that it was her father, and he should take only the dun shaggy filly that has the stick saddle on her.
The Gruagach set as the stakes that he must get the Glaive of Light of the king of the oak windows, or lose his head.
He brought the sword to the Gruagach and, as his wife warned him to, stabbed him to death in a mole.
When he left the next day, she pushed it so it was steady on the ledge, and told him she was afraid it would be hurt.