Psychology experts generally agree that Malignant Narcissism consists of a combination of aspects of narcissistic personality disorder and antisocial personality disorder as well as paranoid traits. In the traditional definition, Malignant Narcissism is often combined with Anti-Social Disorder and psychopathology.
According to Elan Golomb, PhD in her book Trapped in the Mirror. New York: Morrow (1992), pp. 19-20, pathological narcissism occurs in a spectrum of severity. In its more extreme forms, it is Narcissistic Personality Disorder (NPD) (level 3) and Malignant Narcissism (Level 4).
For my purposes here, I define Malignant Narcissism as “any trait or behavior that is designed to inflict pain upon another person, or in any way compromise another person for the specific purpose of gratifying the Narcissist.”
My belief, stemming from experience, is that most Narcissists — if not all — are Malignant/Sadistic to varying degrees, even those who may not have the disorder itself (NPD) but simply several traits that can only be described as narcissistic.
Notice how similar the definition is to Webster’s definition of evil: [Evil is] “anything which impairs the happiness of a being or deprives a being of any good; anything which causes suffering of any kind to sentient beings; injury; mischief; harm; – opposed to good.” Webster’s Dictionary
See also: Narcissism Spectrum