I learned about malignant narcissism at church. What happened was one of my "friends" turned out to be a covert narcissist. This is someone who doesn't display the usual signs of this moral disorder, but is every bit as dangerous as an easy-to-spot narcissist, if not more so.
Covert narcissists often appear unusually pious. Church provides the perfect prop and a steady supply of naive targets who believe that everyone they meet in a religious environment must be good. (I was once naive as well.)
What happened next was very similar to workplace mobbing. These incidents are often started by a single person, but then take on a life of their own as others get involved. Malignant personalities have a superhuman propensity to sow discord. They are also skilled liars and smooth-talking politicians. Because they seem so holy, people believe whatever they say.
I also remember another incident from earlier in my life, involving a disordered personality I had met at work. Although this person had it in for me, she didn't get very far, because I had too much support. Two of my other coworkers were of sterling character, and did not put up with her baloney. A narcissist can only launch all-out warfare if others let them.
I think this story is worth telling now, because it underscores the fact that abuse only happens when bystanders agree. These "neutral" parties share the blame because they could insist the bully behavior stop. However, in a work setting, this is easier said than done. Because of these strong allies, I didn't suffer. (At the time, I didn't realize I was dealing with a malignant narcissist who had prominent sociopathic traits.)
Our direct supervisor was aware of the problem. She chose not to stop it. She was a nice person, but her weakness was that she idolized the abuser. Unfortunately, this had tragic consequences for her. When I gave my notice, for unrelated reasons, she begged me to stay and promised to reign in the problem worker. But I was moving on because I had found something more related to my field.
Anyway, after I left that job, some disturbing incidents came to light. The unpleasant person had always spent a lot of time away from her work station, and, instead, sat at the office computer. (This was before everyone had computers at their desks.) No one questioned this, including our supervisor. Later, it was revealed this woman had hacked into the company insurance system, and was rerouting medical claim payments in her direction. She ended up in jail. Unfortunately, our supervisor was deeply wounded by this betrayal, and apparently, never recovered from the blow. She died a short time later.
This brings up two more points. Malignant narcissists, even if they aren't serial killers, are extremely destructive. But, in the end, they always manage to destroy themselves.