Set in and around the Boston area, Fallout 4 introduced the post-apocalyptic Commonwealth, along with the shadowy organization lurking beneath its surface. It’s impossible to ignore the Synths roaming the wasteland, and the impact they’ve had on the lives of the locals, as they play pivotal roles in the main plotline. However, there is also a more familiar Fallout enemy found throughout the Commonwealth with a horrifying link to the artificial creations.

The idea of the Institute and Synths was first established in Fallout 3 with the quest “The Replicated Man”, which teased the concept of human-like synthetic lifeforms in the Fallout universe. The main plotline of Fallout 4 takes that a step further, adding to the feeling of tension throughout the Commonwealth with the idea that anyone could be secretly replaced, even hinting that the main character could be a synth. However, as dark as that suggestion is, how the Synths were made is far worse than anyone could imagine.

How The Institute Made The Gen 3 Synths

The Awful History Of The Institute’s FEV Lab

To understand how the Synths are linked to another Commonwealth threat, it is necessary to go back to 2178 and the beginning of the project to create them. The project started as part of the BioScience division, under the supervision of Dr. Elliott and Dr. Frederick, who began working with the Forced Evolutionary Virus (FEV). The goal was to adapt strains of FEV in order to combine them with human DNA, which in turn could then be used to grow or manufacture synthetic humans.

There is plenty of debate within the Fallout community about where the Institute could have gotten a sample of FEV from, with Dr. Elliott’s report simply stating that he didn’t want to know. Some believe that it came from Vault 87 in the Capital Wasteland, while others think CIT might already have had it thanks to military connections. However, there is a strong case to be made that the Institute got its hands on a variant of the West-Tek version seen in Fallout 76.

With their dull green skin, Super Mutants in the Commonwealth look more similar to Fallout 76 Super Mutants than the yellower Fallout 3 version. It is also unlikely to be a military strain, as the Commonwealth Super Mutants are significantly less intelligent when compared to their West Coast versions, which were created by the Master. Wherever the sample was obtained, the result was hundreds of Super Mutants dotted throughout the Commonwealth as the Institute continued its research.

Where The Commonwealth’s Super Mutants Come From

The Quest For Synths Creates Problems For The Commonwealth

As the Institute pushed forward with its experiments to combine FEV with DNA, the scientists needed samples, which came in the form of test subjects. Unfortunately, in true Institute fashion, these were not willing volunteers and were often Commonwealth citizens snatched from their lives never to be heard from again. Not even the Institute’s own members were safe from the project’s need for subjects, with minor infractions punished with experimentation. This can be seen with Edgar Swan, better known to many in Fallout 4 as the Super Mutant behemoth Swan, found in Boston Common.

Notes found throughout his shack tell Swan’s tragic story from a low-level Institute worker to an abandoned science experiment. After stealing a pack of cigarettes, Swan joined the ranks of kidnapped Commonwealth residents who were being subjected to FEV. After an initial jump in intelligence, Swan rapidly declined, sadly all too aware of his condition the entire time. When it was finally realized that Swan’s mutation was unstable, he met the same fate as many of the other subjects of the project.

It can also be assumed that the Institute experimented on other Commonwealth creatures such as dogs as Mutant Hounds are also present.

When visiting the abandoned FEV lab in Fallout 4 as part of Virgil’s quest, terminal entries explain what the Institute did with the Super Mutants it created. The reality is chilling as they are simply listed as “discarded”, meaning that any who were unfortunate to survive the experiments were just sent to the surface, now the rest of the Commonwealth’s problem. And by 2224, Dr Elliott had reached the conclusion that the people of the Commonwealth had too much radiation exposure and a new source was needed.

How The Synths & Super Mutants Are Connected

A Terrible History Littering The Surface

Finally, after almost a century of experimenting on kidnapped people and then releasing them back out into the Commonwealth, the Institute was able to perfect the process enough to create Gen 3 Synths. This is achieved by the Institute using DNA gathered from Shaun, who had been safe from the radiation above ground frozen in Vault 111. However, even as the Synth production began and had its own Organics Project separate from the FEV experiments, the lab remained active. The experiments continued, yielding the same results over and over.

Because of the use of FEV in their genetic makeup, Gen 3 Synths are sterile, just like Super Mutants, and unable to have children.

For decades after the first successful Gen 3 Synth, the Fallout 4 faction continued to kidnap and turn Commonwealth citizens into Super Mutants. To add insult to injury, even the project’s lead scientists didn’t know why, with Dr Syverson expressing confusion in 2277 and finally Dr Virgil outright requesting the project be shut down in 2286. Eventually, the project would end, but only thanks to Virgil’s destruction of the lab during his escape in 2287, shortly before the Sole Survivor wakes up in Vault 111 at the start of the game.

The horrific reality of the Institute’s FEV/Synth experiences continued far longer than it needed to and are directly responsible for the Super Mutants found in the Commonwealth and surrounding areas. It’s unclear why Father continued the project and refused to shut it down, but it is heartbreaking to think that each Super Mutant encountered in Fallout 4 was once someone’s loved one. But in their quest to redefine mankind, the Institute recreated one of the oldest threats and then littered the Commonwealth with their discarded failures, no doubt resulting in even more death.