Kathryn Merteuil in Cruel Intentions. Kathryn's personality is a very complex and elusive one. The few who know the real her believe she is an emotionally unstable psychopath (possibly with borderline personality disorder or BPD) She's extremely manipulative and callous. Her charming and brilliant persona seduces everyone around her. Although she's very intelligent, she lacks empathy, sympathy and a conscience. She is also completely self-absorbed.