About 300 years ago, there was a French fur trapper who lived near Fort Pontchartrain du Détroit. Unbeknownst to him when he moved there, he possessed a unique genetic mutation. It was upon the birth of his first child that he noticed the effect, even if he didn’t understand that cause at the time. Everyone with that particular allele had their brains networked together functioning as a single mind with several bodies. An odd interaction with an unrelated protein code that was closely located to this allele on the chromosome caused it to be Super Dominant in that if present on one Chromosome, it would become duplicated on the other one. Only a tiny fraction of children end up not carrying the allele.
So, this fur trapper found that as he had children, instead of them having their own consciousness they simply became a part of the hivemind. When the fur trapper died, the conscious mind did not as there were around a dozen living bodies by that time (children and grandchildren). Over the next three centuries, the hive mind has expanded greatly. This included a directed push during the 1800s to have male bodies volunteer as sailors and do their best to spread the hivemind into the local populations of every port they visited. At the same time, female bodies would aggressively pursue marriages that would have them move up in social status. Later years would see some withdrawal from concentrating effort on this kind of spread, but opportunities are still taken when they present themselves.
In the present day, the hivemind consists of millions of people spread throughout the world. Their numbers are most concentrated in port cities (especially Detroit itself) but they can be found in any human population. They have infiltrated every social strata of society. They could be the homeless man on the street corner, and they could also be the leader of your nation. Because of largely living an experience separate from the rest of human society, they do not see themselves as a part of human society. They might have positive bonds with particular humans, but they largely see themselves as above the law.
However, they cannot operate openly. Even if there are millions of them, they still only occupy a tiny fraction of the total human population. Less than 1 in 1,000 people are a part of the hivemind. So, if people knew that this hivemind existed and wanted to eliminate it, it would be possible. Even if normal humans didn’t win the fight, it would be devastating enough that the hivemind doesn’t want to pick that fight. So, they operate in secret.
As it turns out, a hivemind of millions of people spread worldwide is very effective in organized crime. Smuggling is a sinch in places where the hivemind has one of their bodies conducting port inspections. It’s also very easy to hide dead drops because the location can be different every time, different people can pick it up, and there is no traceable communication outside of the drop. It is also impossible to investigate by following the money because where the money is spent is almost always different from the bodies doing the crimes.
Assassinations are also very easy. When literally anyone can be the assassin and can have instant communication with anyone else as a spotter, no one is safe. Sometimes, the hivemind finds it worth it to lose a body and uses a “lone madman” as a cover. Other times, it is a simple matter to arrange an accident. A teen driver losing control of their vehicle might be seen as a tragedy, but few will suspect them of deliberate action. Similarly, if a body needs to be hidden it can be easily moved through the same channels that goods are smuggled.
There are rumors in the criminal underworld of this cartel operating, but no one seems to have any idea who anyone involved even is. Too many convenient “accidents” have happened to rival crime lords for members of the organized crime community to believe anything else. The police have heard these rumors and have a decent profile for how the cartel is presumed to act, but have little evidence they even exist. Some investigators believe it to be superstition and have likened it to ancient cultures developing myths. Of course, the hivemind is present in both groups and does its best to steer attitudes to where it wants them. On rare occasions, someone might find a stranger on the street handing them a note telling them it fell out of their pocket. The stranger is always someone the receiver of the note would see as harmless, often a young girl.
From a psychological standpoint, how the hivemind works can be quite interesting. Due to subtle neurological differences in the male and female brain, the hivemind has begun to develop a male and female split similar to how normal humans split tasks between left and right brain. It means that while everything is synchronized, certain tasks tend to be physically performed in certain brains, and which brains are used for which tasks subtly affects the outcomes.
Also, while the conscious mind exists as a single entity, the subconscious mind is more networked together and the unconscious still exists completely independent in each body. So, even if all of the bodies are a part of the same conscious mind, they don’t share things like muscle memory. Similarly, more primitive instincts such as hunger and sex drive will exist separately in each body. The greater hivemind might have an understanding of emotions and personal connections felt by each body, but they will be stronger with certain bodies. It’s similar to how a normal person might feel perfectly comfortable doing something with their left hand but it feels wrong and out of place with their right.
It was certainly confusing for the hivemind the first time a female body was mature enough to have its own sex drive. Suddenly people who were considered unattractive by the hivemind up to that point were seen very differently when gazed at with the right set of eyeballs. Also confusing was discovering that attraction could be felt from one of its bodies to another. Bodies raised separately did not experience the Westermarck effect (even if the name wasn’t known at the time). The hivemind initially shied away from acting on this urge, but after encountering it enough time, they experimented with bodies that were only distantly related. The hivemind has now confirmed that they are capable of perpetuating themselves in the absence of other humans.
The hivemind is aware that if it continues to expand exponentially, it is only a matter of time before it takes over all of humanity. It is currently debating a few different options. One is to keep growing and erase non-hivemind humans. A second option is to reach a critical mass where it can take over but keep non-hivemind humans around for companionship almost like pets. A third option is to find a percentage of the population that is comfortable and simply remains hidden. The hivemind has yet to decide and figures it still has time to think about it.