The Gatekeeper Narcissist

A hallmark of a Narcissist is being the self-appointed "gatekeeper" of a group, club, community or workplace, but not in a good way. While the "gatekeeper" position is often a normal part of many groups, an integral function is to welcome new people genuinely and openly; rejecting new people or current members is rare and only done when a person is found to be actually dangerous.
The Gatekeeper Narcissist does not welcome one and all to join, even if the group is supposed to be open and public. Only those who do not threaten the ego or personal agenda of this person are welcomed into the group. For example, anyone who the gatekeeper narcissist believes is more talented, smarter, better looking, nicer, or more charismatic than he or she is will be kept out of the group with any means possible, or made to look bad to everyone else if they do get past them. Anyone who has seen through their agenda will definitely be kept out, even if they have no ill intent. This rejection will be fictionalized to anyone who asks; it will be said that the person is undesirable in some way; they are too weird, slutty, stuck-up, untalented, prima dona, unworthy in some way; the nastier the better; it has nothing to do with reality. This person could be as kind and humble as Mother Theresa, but will be painted by the Gatekeeper Narcissist as a "rotten apple" somehow.
The preferred method is directly discouraging a person by treating them with disdain and arrogance, sending a "message" directly to the person that they are "unwanted". This is often done by only one or two people, but to the target it can be daunting, and there is no way to know if the whole group is similarly arrogant and cold. (Of course, half the time the rest of the members have no idea why this person stays away from the group, and to the Gatekeeper's delight, they often assume that the person either was not interested, or didn't like it.)
It is a rare person that ever stands up to a Gatekeeper Narcissist, because doing so often results in major drama, and whoever the Narcissists sycophants are will turn on the whistleblower. People seem to know instinctively that standing up to a Narcissist who has the smallest amount of influence will enrage them, and he or she will trash them to kingdom come. Only the bravest of us will risk the drama that is sure to follow. Unfortunately, most of the time the Narcissist Gatekeeper is left in his or her "position" because those who are aware of them don't want to deal with the fallout.