Synth

Synth (short for synthetic humanoids, also called androids or artificial humans) is a common term used to refer to the bio-synthetic robots manufactured within the Institute's laboratories. Synths can range from early skeletal models to those nearly indistinguishable from human beings, save for a specific implanted component only discoverable after death. They are found in the Capital Wasteland in 2277 and in the Commonwealth and the Island in 2287.

Nomenclature
Both android and synth are technically correct terms, used interchangeably by the Institute to refer to its creations. The former term has been deprecated at Shaun's insistence, following the introduction of third generation models.

Synths are all issued a four character identification number when processed and assigned duties. It always begins with a letter, followed by a number, dash and two more numbers. The precise system governing designations is unknown. The M prefix identifies a known infiltrator synth (M7-62) and a synth that infiltrated the structures of the Brotherhood of Steel (M7-97).

Background
Synths have been manufactured by the Institute for decades, with no precise date as to when first generation synths were fielded to the Commonwealth; however, it was at a time when the Institute had not yet become the major bogeyman of that region and were able to continue their work in relative peace. Further attempts to work peacefully with the native inhabitants of the Commonwealth eventually culminated in mutual mistrust that ended any possible relationships between the two rather quickly.

By the 2170s, the first generation synths were no longer enough for the Institute's needs, and in order to overcome the limitations of limited and non-renewable materials, the Institute endeavored to create synthetic flesh, so that their creations could more safely traverse the above world. Research into this officially began in 2178 under the auspices of Doctor Frederick, on F.E.V. samples, despite the objections of some senior members of the BioScience division. Both women and men were abducted from the Commonwealth and submerged in the Institute's modified FEV, their mutations carefully tracked and extensively investigated. Successful mutations would be monitored to ensure survivability, then tagged and discarded. The research was intended to produce effective synthetic organics, but it ground to a halt in March 2224, as the research team concluded that the organic synth project could not proceed despite perfecting two FEV strains for the project. Radiation-induced hereditary damage proved too much of an obstacle.

Just three years later, in 2227, the organic synth project was spun off from the FEV research initiative due to the acquisition of Shaun and his undamaged pre-War genetic code. He was recovered by Conrad Kellogg, and his DNA became the basis of the third generation of synths in a project led by Dr. Walter. The infant Shaun became Father to a whole family of engineered synthetic beings. Of course, tests were not without setbacks; in 2229, a defective 3rd generation infiltrator caused the Broken Mask incident, vilifying the Institute in the eyes of the Commonwealth. The synth, which called itself Mr. Carter, was a prototype that was field tested without the Institute director's approval. After an apparent malfunction, Carter went on a shooting spree, murdering at least four people before being brought down by Diamond City Security and revealed to be a synth. Though the Institute did not actually intend to massacre the people of Diamond City, the people of Diamond City have feared and resented the Institute ever since.

Meanwhile, existing first generation units were provided with a suite of upgrades, in order to increase their functionality and allow for increased deployment into the Boston ruins. Designated as second generation synthetics, bridging the gap between the skeletal and human-like synths, these models are characterized by thick artificial skin. These second generation synths continued to serve the Institute well into 2287, along with the first generation remnants, although plans were made to gradually retire both the first and second generations in favor of organic synths, with the remainder of the mechanical units relegated solely to surface duties.

Nick Valentine and DiMA are unique synths, both being prototype synths intended to bridge the gap between the Gen 2 synths and the truly sapient Gen 3 synths. While DiMA was made to freely develop a personality from experience, Nick's personality was built upon the mind of a pre-War detective who had his mind encoded from a pre-War brain scan, giving him all of the memories and experiences of his namesake. The two of them escaped the Institute together, but due to the limited memory space of their prototype brains, Nick's memory of the escape was deleted. This led him to believe that he was thrown out by the Institute. DiMA later traveled to the Island and founded the synth refuge of Acadia with Faraday. As DiMA reached the limit of remaining space in his prototype brain, he began to artificially increase his memory capacity by storing his memories in connected computers.

First generation
The first models created by the Institute are skeletal creatures with an unmistakable provenance. Patterned after the human silhouette, their basic chassis consists of a human-like skeleton constructed from alloys, with the power cell and additional mechanisms stored where the chest cavity would be, while visual receptors and the primary processing unit are contained within the artificial skull. Limbs are minimalist, articulated by a network of tensile fibers, simulating muscle action, like in early human prostheses.

In practice, first generation synths are simple, yet effective machines. They are employed by The Institute for menial labor within the Institute, maintaining the hundreds of systems keeping the underground habitat in operation, and performing tasks that can be easily automated. Like all robots, they can take large amounts of damage, almost never backing down from a fight even with their limbs blown off. What the Gen 1 synths lacked in ability or strength compared to later models, they made up for in expendability and numbers, always capable of being replaced by the Institute.

However rugged they are, they have major flaws. While capable of recognizing human speech and interpreting commands given to them, they require careful programming and instructing, as well as patches to keep them in operation. The most notorious functionality of first generation synths is navigational software, which requires frequent patching and fixing. Pathfinding software frequently causes first generation synths to try to walk through walls.

Second generation
The most common variant of mechanical synth in the Commonwealth, second generation synthetics are essentially Gen 1 synths provided with a suite of upgrades to their mechanisms and programming. The most noticeable difference is the inclusion of an internal mesh that shields the mechanisms of the synth from damage and provides support for the artificial skin layer that makes the Gen 2 similar to a human. Though more humanoid in appearance, Gen-2s still possess limited A.I. and superficially resemble a mannequin more than a human. These synths are often found dressed in synth armor when on the surface, or else in Institute jumpers when working down in the Institute. They also speak in a robotic voice, but at a much lower pitch than Gen 1 synths.

The Gen 2 synths are primarily used on the surface, where the artificial skin layer and improved mechanics improve their performance well above that of Gen 1s. Gen 2 synths are primarily used for resourcing operations and are the primary workhorse when scouting the surface. They are feared, as they're usually witnessed stripping entire settlements down for parts and killing everything that gets in their way. One of the latest targets of a Gen 2 stripping unit was University Point, which saw its population exterminated for resources.

Of course, due to their mechanical nature, mechanical synthetics can suffer from major software bugs, for example, causing them to remain in a single room executing its duties in a loop due to faulty navigation software. Other failures are typically mechanical in nature, with their servo motors and drives breaking down due to age. In fact, most second generation synths have lasted long past their projected lifespans, with all the bugs that crop up due to overuse. 

Third generation
The most advanced synthetics created by the Institute are fundamentally different from their predecessors. Despite the sequential numbering, they are unrelated to their mechanical counterparts. They are derived from Shaun's pre-War DNA extensively modified using the Institute's own research into the Forced Evolutionary Virus, combining the advantageous adaptations encoded into FEV with the versatility of the human body shape. This allowed the Institute to create varieties of synths of different races and appearances despite the base DNA coming from only one source. They are the result of nearly five decades of research, from 2178 to 2227.

Third generation synthetics represent the pinnacle of synth technology, being virtually indistinguishable from natural-born humans right down to the cellular level. Each Gen 3 synth is built from lab-grown bones, muscles and other tissues that are assembled and brought to life at the Institute's Robotics lab, and are "born" with the bodies and mental faculties of full-grown adult humans. Though entirely biological, each Gen 3 synth contains a neurological implant inside their brain allowing them to be "programmed" and manipulated via voice commands. This implant cannot be detected or removed without killing the synth. Synths are also installed with additional components, such as neuro-servos and other implants.

Third generation synthetics are unlike humans and some liberated synths do not consider themselves human at all. The reasons for this are multiple, chief among them is the assembly process. According to Max Loken, synths do not require sleep at all to function properly, are completely immune to disease and do not require the intake of food or water to generate energy for their bodies certainly contribute. This is in conflict with Curie, who mentions needing to sleep and eat when in her synth body, however, synths can still maintain these functions - or even want to eat such as with synth affinity for Fancy Lad cakes - but may go without depending on circumstances. Generation 3 synths are physically and mentally indistinguishable from ordinary humans, having lab-grown bodies of real human flesh, bones and organs instead of plastic and metal. As Dr. Roslyn Chambers found, no medical tests or procedures can identify someone as a synth without killing them (synths that infiltrate settlements, for example, only drop synth components when killed). Psychological tests, such as Covenant's SAFE test, are dubious at best. However, they are not perfect duplicates and have a few key differences from humans that are not immediately obvious: synths do not age, require sleep, nor can they gain or lose weight.

Views on synths
Many denizens of the Commonwealth have become paranoid and prejudiced against synths, fearing they might be abducted by the Institute and replaced with identical copies of themselves. Their paranoia is justified, as some of the most sophisticated synths encountered act as spies and could fool the unaware. There are some examples of Commonwealth citizens that were murdered and replaced with synth duplicates who the Sole Survivor interacts with on missions if they choose to join the Institute.

The synths' Institute creators view them as nothing more than machines and treat them as slaves. The Railroad has committed itself to freeing Generation 3 synths from their masters and smuggling them out of the Commonwealth to somewhere the Institute cannot reach them. In contrast, the Brotherhood of Steel has sworn to eliminate all synths, for to them, a machine capable of thinking like a man is an abomination of technology and cannot be allowed to exist, likening the lack of ethics used to create them to that of decadent pre-War corporations.

Gen 1 and 2 synths are less intelligent than Gen 3 synths, but display a level of sapience, as exemplified in their dialogue. They call out to their target "whoever you are, I know you're there" and will comment that their systems may be in need of recalibration if they lose track of a target. During the Tradecraft quest, Deacon comments that Gen 1 and 2 synths are on a similar mental level to protectrons and other pre-War robots, causing some debate among members of the Railroad as to if Gen 1 and 2 synths are worth trying to rescue.

Characteristics
While most synths are Gen 1 or Gen 2 and are thus allied to the Institute, they can also be encountered in other places.

If the player character has built a radio beacon, incoming settlers have the potential to be Gen 3 synths (non-infiltration). If these settlers are put on a supply line and happen to pass any major Brotherhood of Steel encampment (Cambridge, etc.) they will be fired upon by the entire station, stalling any building the player character can do.

Synths can also be a part of a Minutemen patrol if the Sole Survivor has retaken the Castle and has an ample amount of well-off settlements. If a Minutemen patrol that possesses these synths passes a Brotherhood encampment, they will not be fired upon. Sometimes their patrol routes take them straight through the Boston Airport, into the courtyard of Fort Strong, and back through again. They will not fire upon each other and will sometimes pleasantly engage in dialogue with each other.

If the player character has established a bad reputation with the Institute (in other words, completed the quest Banished from the Institute), the Sole Survivor's settlements will often be infiltrated by synths who will eventually open fire on the player character's other settlers.

This will be a rare occurrence after the Institute is destroyed.

Gameplay attributes
A synth's limbs will be destroyed when crippled, which will affect a synth in different ways based on its armament. Should a synth's legs be destroyed, it will sit in place and fire upon the player character. A synth armed with a pistol can continue to fire while down after having its left arm destroyed, a synth armed with a rifle must have both arms intact in order to attack. Should a synth's arms be destroyed, they will continue to attack by striking the player character with their electrified stumps. A synth that has its weapon arm and a leg destroyed will be effectively removed from combat, and will not even attempt a melee strike if the player character wanders close.

Synth
Synths often come in groups of four or so, armed with Institute weapons.

Synth strider
Stronger than an ordinary synth, these striders, while fairly weak, are still a significant step up. They, like their counterparts, almost exclusively use Institute weapons and in some instances, shock batons.

Synth leader
Unlike most synths, leaders are armored and possess heavily modified Institute weapons. They almost exclusively travel with other synths and often act as the final opponent in synth occupied areas.

Synth patroller
A step up from the synth strider and leader variants, the patroller is stronger and has better aim. They are usually seen in groups with other synths, such as synth striders or leaders, and are usually seen with Institute pistols or rifles.

Synth seeker
A variant even stronger than the synth patroller. As with other synths, they can be found traveling in groups. Usually seen with the same weapons as the synth patroller.

Synth trooper
Synth troopers are the standard Institute soldier and more aggressive than most of their counterparts. They usually spawn in weaker packs of synth striders or occasionally patrollers.

Synth assaulter
The synth assaulter is a mid-to-high level synth, that is the first variant to be equipped with synth heavy armor.

Synth stormer
The synth stormer is a high-level synth, often seen with other high-level variants of synths equipped with sturdy or heavy synth armor.

Synth eradicator
The synth eradicator is the strongest variant of synth. Boasting strong weapons and armor, they are on par with Brotherhood knights.

Institute courser
The courser is the strongest variant of synth, on par with the Brotherhood star-paladins, and possess a stealth boy along with strong weapons and high endurance. It can summon various synths through the teleporter grenades.

Fallout 3

 * Armitage (S3-47)
 * Harkness (A3-21)

Appearances
Synths appear in Fallout 3 and Fallout 4. The two synths encountered in Fallout 3, Armitage and Harkness, were ostensibly Generation 3 synths, and Generation 1 and 2 synths were not introduced until Fallout 4.

Behind the scenes

 * Bethesda designers took inspiration from vintage artificial prosthetic limbs in creating the model for the synth as it appears in Fallout 4, and saw creating a new version of the "classic android endoskeleton" as a fun challenge.
 * The exact distinction between Gen 1 and Gen 2 synths is somewhat vague. In the game's files, there are three types of non-Generation 3 synths, not two. Some are unambiguously Gen 1 synths and spawn with a completely exposed mechanical skeleton and typically do not use armor, as seen in Kellogg's memories during Dangerous Minds. On the other hand, some are unambiguously Gen 2 synths and have intact "skin" which can only be damaged by crippling their limbs, expressive faces, and typically wear clothes, such as the synth requisition officer. In between these are synths with rigid plastic skin, which typically spawn at least partially damaged and can be blasted off by the player character even without crippling limbs, similar to other robots. The last group could represent Gen 2's that have begun to decay, but given the more rigid appearance of their skin, they appear to be an earlier model.
 * Synths share many similarities to the terminators from the Terminator film franchise. One is that the Generation 1 synths are nothing more than endoskeletons that loosely resemble a human skeleton, just like the majority of terminators created by SkyNet. The Generation 2 synths differ in that they possess artificial skin like the T-600 terminators shown in Terminator: Salvation. The Generation 3 synths were designed to look exactly like human beings so that they can infiltrate human settlements undetected, which is the exact purpose of the T-800 infiltrator seen in every Terminator film. Sometimes, when in combat with Gen 1 and Gen 2 synths, they will say to the player character "You must be terminated."
 * The Generation 3 synths are quite similar to the Replicants from Blade Runner, based on the novel Do Androids Dream of Electric Sheep? by Philip K. Dick, in that they are synthetic humans genetically engineered entirely out of organic substances and are virtually indistinguishable from real human beings. The author, Philip K. Dick, explored ideas of different types of conscious beings as equal with humanity, and the human reaction to these rival sentient beings.
 * Synths also allude to Star Trek's androids. Both have human variants such as Data and Gen-3 synths. There is controversy on what to call them, androids or synths, synths being short for synthetic humans. Both have controversy as to whether they are people or not, as Data, at one point, was threatened to be dissected and used to create more, saying he is not a person.