A malignant narcissist working solo is virtually powerless. He or she (this blog, by the way, is focused on female bullies) needs a string of cohorts. Oftentimes, these individuals also have strong narcissistic traits. We've all heard the expression that "water seeks its own level." In this case, that's definitely true.
Hanging out with the chief bully gives them a sense of kinship. They feel righteous and empowered, because the bully has primed them to do her dirty work. These weak-willed enablers can inflict a great deal of the pain, while the main narcissist watches it unfold, as if she's viewing a movie.
I've long wondered how such like-minded people always manage to find each other, and then, somehow, quickly form a group. This is something I haven't quite figured out, even after observing malignant narcissists in action. This, to me, remains a mystery. All I can gather is that narcissists and sociopaths (there's a lot of overlap) are acutely aware of other people's weak points, and they play upon these defects to get others to follow through on their wicked plans.
For example, they might sense someone in their cluster has a strong need to fit it and to belong. They will use this insider information to get them to attack the target. However, if this enabler still has a bit of human decency, the narcissist directs things so the attack doesn't conflict too much with their values.
Another person, though, may have a mean streak, something the narcissist will make sure is fully exploited.