The Lady of the Cold is a winter-spirit that visits the Moomin-valley every winter and an antagonist from Tove Jansson's book Moominland Midwinter and the 1990 Japanese anime series Moomin.
Appearance
Unlike most key characters in the Moomin books, the Lady of the Cold is never shown in its illustrations. Probably this was a a consious decision by Tove Jansson in order to make the character more enigmatic. The result of this has been that every adaption of Moominland Midwinter has presented widely different incarnations of the character, designed entirely by the producers of that particular adaption.
In the 90s anime, her body is made out of ice and is slightly egg-shaped, with a round head on top. Her face is almost doll-like a tiny mouth, nose and large expressive eyes. She wears a crown made out of icicles and has two thin arms with star-shaped hands. Her three legs are also very thin, and has stars instead of feet.
Personality
She has no dialogue, and only communicates through action and expressions.
The Lady of the cold is said to visit Moominvalley every winter, for unknown reasons. She does seem to appreciate gifts during her visits.
In many respects, she seems to be the counterpart of another villain of the series, The Groke. Both are incarnations of winter itself, but while the Groke can't control her abilities and is usually non-hostile, the Lady can and is fully willing to use them against anyone. She froze little My , a young child, solid simply because she looked at her face. In the original book, she did the same thing to an absent-minded squirrel, who was looking for his lost cone. Her refusal to let anyone look at her face might imply a high level of vanity and narcissism.
However, she do seem to be relatively merciful, as both My and the squirrel were alive and well once they had been warmed up, though the case of the latter case is uncertain. (See Trivia for more information.)
Another difference between the Lady and the Groke is that while the latter freightens people by her looks, the former lures people towards her with her appearance.
Powers and Abilities
She has the ability of flight.
Her most notable feat is the ability to freeze people solid simply by looking them in the eye. The Groke fears her greatly, implying that the spell is even effective against her. The victims usually survives though.
She can also bring life to inanimate objects, like Too-tickys snow-horse. Since she is a winter-spirit however, this might be limited to objects that are made out of snow.
Trivia
In the book, the squirrel's fate is ambiguous. The Lady's gaze literally freezes him to death. Moomintroll and his friends hold a funeral for him, but the frozen ground makes it impossible to bury him. An unexpected help arrives in the form of the snow horse built by Too-ticky for the Lady of the Cold, who has mysteriously come to life. The horse walks the company to the beach, where it takes the squirrel and gallops towards the horizon. In the next spring, Moomintroll meets a new squirrel who also calls itself by the same name as the previous one. He seems to have just as bad a memory as the first squirrel, as he can't recall if he meet the Lady of the Cold or not. It's never clarified if the squirrel survived the encounter with the Lady of the Cold or not.
The case with the squirrel makes the Lady of the Cold, together with Edward the Booble, one of the only two characters in the Moomin books who has succesfully killed someone.