Lady of the Green Kirtle

Presented only within C. S. Lewis's The Silver Chair, the Lady of the Green Kirtle has no genealogical or mythic provenance given in the canonical text. She appears as an independent malign witch who has established dominion over an underground realm (often called Underland in secondary commentary) and has acted over at least a decade to enslave Prince Rilian and suborn subterranean peoples in a plot to conquer the surface world of Narnia. Later editorial sketches and adaptations sometimes label her 'Queen of Underland' or conflate her with other Northern Witches, but Lewis's original novel provides no further origin or backstory.

In human guise she appears as a seductive and beautiful woman, notably distinguished by a green kirtle (the garment referenced in her title). In the climax of the novel she transforms into a gigantic green serpent: her arms are described as fastened to her sides, her legs intertwined and effectively disappeared, and the long train of her green skirt thickening into the writhing serpentine body.

Narratively she practices potent witchcraft: she enslaves Prince Rilian and a host of gnomes, poisons Rilian's mother (Ramandu's daughter), and plans to use her captives to take over Narnia. She employs hypnotic and illusionary magic that aims to dull senses and undermine belief (attempting to convince intruders that Narnia and Earth do not exist). She is also a shape‑changer, becoming a giant serpent whose form is fused with her green kirtle; this transformation is used for lethal violence and is ended when Rilian kills her by decapitation after recognizing her.