Who Is Nimue (Viviane)?
The lady of the lake who imprisoned Merlin
Nimue is one of the Ladies of the Lake in the Arthurian legend. She was loved by the wizard Merlin and learned magic from him. In some versions of the story she is known by other names, such as Viviane.
In Episode 5, she learns sorcery from Merlin, who will not leave her alone, and then uses it to trap him beneath a great stone in Cornwall. Merlin knew his fate in advance, yet out of love he would not leave her side. At the same time, she appears at Arthur's fight with Accolon and uses her magic to make Excalibur fall from Accolon's hand, saving the king's life.
In Malory's stories, she later marries the knight Pelleas and goes on rescuing Arthur from danger. Readers differ on whether she is a villain or an ally.