The Lady of the Lake is an important figure of Arthurian Legend and medieval storytelling. She is often mentioned to have enchanted Merlin.
In the Land of Stories series, she appears in Beyond the Kingdoms, chapter 24.
Appearance and Personality
"A geyser of water rose out of the lake like a fountain in slow motion, twisting and looping through the air until it formed the shape of a woman. Like a heartbeat, every few seconds a ripple started at her chest and traveled through her whole body."
The Lady of the Lake, or Nimue, as Merlin calls her, can change her appearance and command the water of the lake at will. She works hard keeping the water of her lake clean and scares off any birds bathing in it. She has a history with Merlin; he says they were never together, and she trapped him in a cave for a month against his will; Nimue calls him her lover and claims it was romantic.
Mother Goose, with her charming way with words, calls her "H2O", "Oversized Puddle", "Lunatic of the Lake", and "Wet Wench". Merlin chips in and calls her "Miserable Pond".
When Alex and Arthur want to collect a part of the old tree on the island in the middle of the lake, Nimue is pleased at first, saying she doesn't get visitors very often. When she finds out they are on friendly terms with Merlin, she loses her cool and traps them to lure Merlin to her. Nimue treatens to harm Alex and Arthur unless Merlin comes back to her. When he grudingly agrees in order to save them, Nimue fails to keep up her part of the deal and tries to harm them anyway. Mother Goose steps in and evaporates the entire lake.