Synth

Synth (short for synthetic humanoids, also called androids or artificial humans) is a term used to refer to the bio-synthetic robots manufactured within the Institute. Synths can range from early skeletal models to those nearly indistinguishable from Human beings, save for a specific synth component only discoverable after death. They are found in the Capital Wasteland in Fallout 3 and in the Commonwealth, Nuka-World, and the Island in Fallout 4.

Nomenclature
Both android and synth are used interchangeably by the Institute to refer to its creations. Android has been replaced inside the Institute at Shaun's insistence, following the introduction of third generation models. In the Capital Wasteland, they are almost exclusively called androids, with the sole exception of Harkness, who refers to his kind as synths. In the Commonwealth they are exclusively called synths.

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 M prefix is seen in use with M7-62 (Mayor McDonough) and M7-97 (Paladin Danse). Coursers use designations beginning with X or Z. There are exceptions to these rules however, as shown by A-2018, XPN-20A, Z4K-97B, and B-263.

Background
Synths have been built by the Institute for a long time, before they were known as enemies to the Commonwealth. They attempted to use them to work with the surface, but were stopped by mutual mistrust.

In August of 2178, Doctor Frederick started work on making organic synths, using his own F.E.V. samples, with the permission of the Directorate. His coworker in Bioscience, Doctor Elliott, objected. 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, tagged, and discarded. By March of 2224 however, the research had stalled, as while they perfected two strains of FEV, all samples of human DNA were too badly damaged by radiation. In addition, multiple other BioScience doctors had joined Doctor Elliot in objecting to the FEV research. Elliot himself came up with a plan to obtain pure DNA, but felt very uncomfortable about it as well.

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. Synths are constructed with advanced CPUs and streamlined power systems, although they are incompatible with pre-War robot hardware, nor can synthetic limbs be installed onto a robot chassis.

First generation
Gen 1 synths have been produced since before the Institute cut all ties with the surface, and have performed continuously long past their projected lifespans.

Gen 1 synths are mechanical in nature, and like robots can have many of their limbs destroyed but still survive. They do not however, self-detonate both of their arms are destroyed. They also use weapons and tools like humans do, not built in. While Gen 1s are considered old and less advanced than their predecessors, they are still highly advanced compared to a Pre-War robot such as an Assaultron.

Conrad Kellogg noted that Gen 1s were not great, but the Institute could produce them in numbers. Deacon similarly notes that a Gen 1 is about as intelligent as a Protectron, which causes schisms in the Railroad as Gen 3 synths like Glory want to liberate them as well, but most human members don't.

While capable of recognizing human speech and interpreting commands given to them, they require careful instructing and maintenance to keep them in operation. Due to age, Gen 1 synths suffer from frequent primary drive breakdowns, and have faulty navigational software, which requires patching. Pathfinding software frequently causes first generation synths to try to walk through walls, and can cause synths to be trapped in the same room doing the same task for days.

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. 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.

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 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 inhabitants 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.

Gameplay
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 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 second 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
In The Art of Fallout 4, concepts were described as taking "vintage artificial prosthetic limbs" as inspiration for a "fresh take on the classic android endoskeleton."