I know a lot of readers are probably confused about the differences between NPD (narcissistic personality disorder), malignant narcissism and psychopathy. I think this article about malignant narcissism from the website The Narcissistic Life describes the differences in a very clear way much better than I could. They are all at different points on the same spectrum, according to most experts.

Malignant Narcissism: http://thenarcissisticlife.com/malignant-narcissism/