In the film, Kathryn is wealthy, beautiful and popular, part of the Upper East Side's social elite.

Portrayed as a manipulative mastermind who uses and destroys people for her own amusement, she is also depicted as being addicted to cocaine, which she hides in her rosary, and it is suggested that she suffers from bulimia.

She hides her true nature behind the facade of a deeply religious model student, fooling everyone she knows, except for her equally narcissistic step-brother Sebastian Valmont (Ryan Phillippe) and ex-boyfriend Court Reynolds (Charlie O'Connell).

Kathryn shows signs of sociopathic and callous behaviour, treating the death of her supposedly "beloved" step-brother with cold disdain, and gleefully enjoying destroying his life, as well as those of the people she perceives as threats or inferior to her.

Kathryn is the archetypal "ice princess" whose opulent bedroom is a cold, dark lair decorated in royal blue and silver with crystal embellishments.

In the film, she's first seen discussing her prep school with Mrs. Caldwell (Christine Baranski) and her daughter, Cecile (Selma Blair).

Kathryn's spotless reputation is ruined when Cecile distributes copies of Sebastian's private journal, made into a book by Annette, titled "Cruel Intentions", which details her manipulations.

Her fall from grace doesn't end there, as Ronald had made a detailed written confession about her involvement and how she lied to him about Cecile no longer being a virgin in order for him to kill Sebastian.

This is made worse when Headmaster Hargrove finds her rosary and discovers drugs hidden in it, her spotless record is ruined.

The film reveals that Kathryn was born to Tiffany Merteuil (Mimi Rogers), a well-respected New York socialite.

Sweeney suggests that 1999 "gave viewers two manipulative dark-haired Queen Bees": Kathryn Merteuil in Cruel Intentions and Courtney Shayne (Rose McGowan) in Jawbreaker.

[5] Richard Burt suggests that Kathryn is "punished for being beautiful and smart" in that she "can't keep guys from dumping her for stupider girls".

[6] Gellar's portrayal of Kathryn was parodied in the 2001 film Not Another Teen Movie, in which Mia Kirshner played Catherine Wyler, "The Cruelest Girl in School".