Psychopath

A psychopath is one who suffers from a disassociative psychological disorder referred to as psychopathy. Symptoms of psychopathy include an antisocial demeanor, a lack of emotional maturity or empathy, a superficial sense of self, and an inability or unwillingness to accept personal responsibility. In television fiction, characters suffering from psychopathy are prone to acts of violence and may even suffer from additional pathological disorders, resulting in criminal activity.

Psychopaths in fiction generally possess a number of standard characteristics which are not necessarily as common among real-life psychopaths. The traditional "Hollywood psychopath" is likely to exhibit traits which make them ideal villains. Said traits may not be present in real psychopaths, sociopaths, or those with borderline personality disorder.

All told, they are total friggin' nutters.