Blodeuwedd is a flower maiden of Welsh myth, created for Llew Llaw Gyffes by Gwydion and Math from flowers and nine elements, because he was forbidden to take a human wife.
She fell in love with a hunter called Goronwy (Gronw), and set about creating a plan to kill Llew by trickery. She coaxed Llew into revealing the manner in which he could be killed; he explained that he could not be killed by day or night, indoors or out of doors, neither riding nor walking, or by any weapon that had been lawfully made. Pressed further he explained that there was a way around this. He could be killed by twilight, with one foot in a cauldron of water positioned by a riverbank, and one upon a billy goat, a form of Celtic triple death. She persuaded him to get into this strange position and her lover Goronwy, who has been hiding in some bushes leaped out and threw a spear made on an unlawful day at him. Llew was sorely wounded and changed into an eagle. He is later restored to human form by magical means, and Blodeuwedd is turned into a night owl for her sins, to wander the world of darkness shunned by other creatures in the daylight.
Some researchers believe Blodeuwedd to be the maiden aspect of the triple goddess.
Courtesy Pantheon of British Mythology at Mysterious Britain.