The late great sci-fi writer Iain L. Banks, author of the “Culture” series, coined the term “hegemonizing swarm” to refer to invading forces whose main objective is to take over and remake other societies in their own images. Hegemonizing swarms are a favorite villain in science fiction–zombies being perhaps the most popular of the trope–and many sci-fi franchises have developed their own version: “Doctor Who” has the Cybermen, “Stargate: SG1” has the Replicators and the Ori, and “Star Trek” has the Borg. Unlike other invading villains who usually seek to conquer and then make use of the resources of the conquered lands and peoples, the first priority of the swarms is to turn everyone they encounter into members of the swarm, destroying all individual personalities as each person becomes part of the hive mind.

Parallels to those who aggressively proselytize are inevitable, and “Stargate” hammers this point home with the Ori, who are first and foremost a religion, promising eventual ascension to a higher plane to all believers. Even when simply making everyone else part of the swarm is the sole goal, there is a religious fervor to the call of the swarm. “Resistance is futile!” trumpet the Borg, while the Cybermen initially used the term “conversion” for the process of turning humans into cyborgs (in the rebooted series, they are “upgraded”).

Hegemonizing swarms are terrifying because it is not possible for individuals to form any kind of relationship to them without being swallowed up and having one’s will erased. There can be no conversation, no exchange of ideas, no appeals to reason or emotions. The swarm cannot think beyond its own message; any other ideas are incomprehensible and ignored. The only option the invaded have is to destroy them.

And that often leads to a moral quandary for the invaded. It’s one thing to destroy all Replicators, which really are mindless machines. But when the swarm member coming at you used to be a person–perhaps a person you knew and loved–that changes the game. Finding a way to unconvert them, to deprogram them, to find the vaccine that will cure them, becomes the priority. But first, there must be the conviction that the swarm member is still there, is still human under the conversion. We must be able to believe that connection is still possible.

For that to happen, the writers of such novels and shows have realized, at least one of the enemy must behave differently, must be relatable in some way. There must be a way to bridge the gap. In “Star Trek: The Next Generation,” where we first meet the Borg, the first bridge is Captain Picard himself. Ironically it is the Borg who realize the need for a bridge and forcibly assimilate Picard, renaming him “Locutus of Borg” and intending to use him as a means of communicating with humans. But bridges go both ways, and the Enterprise crew figure out how to use Picard to send a message to the Borg cube and cause it to self-destruct. Similarly, in “Doctor Who,” Danny Pink retains some of his individuality after conversion. Remembering his love for the human Clara Oswald, Danny is able to use his connection to the Cybermen to force them all to self-destruct.

Hope that the lost ones can be regained is fueled when the Enterprise crew find an injured Borg, sole survivor of a crash who is now cut off from the collective, and are able to restore his human personality; the same thing happens in “Star Trek: Voyager” when the crew of Voyager find and restore Seven of Nine. The knowledge they gain will be put to use when Admiral Janeway is deliberately infected with a neurolytic pathogen and allows herself to be assimilated; the pathogen–an anti-vaccine–spreads among the Borg on the cube and kills them, along with the admiral.

In the final season of “Star Trek: Picard,” the Borg return. Janeway’s pathogen has continued to spread among the Borg and they are dying off. But the Queen comes up with a new way to assimilate humans, using the Borg elements remaining in the body of Picard (who has been reborn into an android body), which are spread when humans use the transporters on certain ships, turning them into Borg who appear fully human. She then manipulates Jack Crusher, the son of Picard, through dormant Borg elements in his DNA inherited from his father, to communicate with the assimilated humans and get them to attack the Federation with its own ships. Picard, knowing he too could be lost, deliberately links with Jack and becomes Locutus once more. Again, it is love that makes the difference; Picard retains enough of his humanity to reach Jack and get him to disconnect from the Queen and the assimilated humans. The Enterprise is able to destroy the last cube and the Queen, and everyone is restored.

The message of all these variations on the theme is clear: in the face of the most implacable, impersonal attack on one’s individuality, there is always hope, and that hope lies in our ability to love and connect with each other and not to give up even when it seems like another person is lost to us forever.