Who is Diane Fleming aka Nina?

Diane Fleming, who is known in Severin’s case studies as Nina, is the villain of the novel. Diane represents the women who commit violent acts even though they do not suffer with PMDD. Diane believed she suffered from PMDD and that disorder caused her to murder her father. She interviews for a spot in Severin’s research but is told that her symptoms do not fit those of PMDD. Diane does not believe this so she has a complete hysterectomy. Even after the surgery, Diane continued to act in violent ways. For instance, she kills Serge in order to protect herself. This continuing violent behavior after the surgery proves that Diane does not have PMDD but is perhaps instead, just a psychopath. Serge says of Diane that she has ice in her heart. He recognized the evil in her nature when he watched the way she enjoyed killing a lab mouse and its babies.