A) You don't really understand karma. Karma does not "take care of the rest." It does not mean good comes to good and it does not exact pain upon those that act with bad intent. Before you discuss Karma, read this article, https://medium.com/illumination/the-real-meaning-of-the-law-of-karma-will-blow-your-mind-f07fe413ebce which is the best I have come across.

B) You do understand malignant narcissists very well. Yet, to tie the disorder to karma and other spiritual concepts, please see my https://medium.com/illumination-curated/life-is-school-for-the-soul-9b081dbe8453 , which gets to narcs in the second half of the essay