Nimue (Once Upon a Time)

Nimue is an antagonist in ABC's Once Upon a Time. She was the true love of Merlin, with whom she went on a quest with one day to make a sword out of the Holy Grail. However, during an encounter with Vortigan, Nimue kills him, having drank from the Grail, and becomes the first ever Dark One.

She is portrayed by Caroline Ford.