“Personal record, Dr. Brian Virgil. This will likely be my last recording.
My requests to shut down the FEV program have repeatedly been denied. We've learned nothing useful in the last 10 years. I have to take matters into my own hands. What we're doing... it's not right. It needs to stop. If anyone should find this after... after I'm gone... know that I never wanted to hurt anyone. Anyone! Do you understand me? I'm going to make sure the whole program is shut down. If not for good, then at least for years to come. After that...I know what I'm about to do will be seen as a betrayal. Treason, he'll probably call it. So... I'm leaving. I have a plan... and if it works, I'll be somewhere safe. Somewhere not even the Coursers can find me. Everything that we've done, the lives we've taken... if there is a god, may he have mercy on us all.”— Dr. Brian Virgil, ex-Institute bioscientist
The super mutants of the Commonwealth are a different strain from either super mutants or those created at Mariposa. While they possess the imposing musculature and resilience of the former, they have a level of intelligence on par with the dumber examples of the latter. Besides having similar habits of super mutants, such as caging prey and bagging body parts, they are also capable of following a chain of command, erecting fortifications, and even setting up traps and ambushes - such as at Trinity Tower, where Fist deliberately used Rex Goodman as bait to lure humans and weed out the weak super mutants among his host. They are also capable of speaking like normal humans, unlike their practically feral brethren from the Capital Wasteland, and consider themselves the superior race of the Commonwealth.
All Commonwealth super mutants are the result of The Institute's research into FEV, which began in August 2178 under the auspices of Doctor Frederick. Research on samples acquired by the team was authorized by the directorate and the program began despite the objections of some members of BioScience. 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. In layman's terms, The Institute was simply releasing super mutants into the wild, creating a scourge on the Commonwealth that lasted for decades and still plagues the Commonwealth in 2287. In fact, the first super mutants attacked human settlements as early as 2180. Their actions were even more heinous considering the fact that in case the mutation destabilized, it would create horrifying behemoths: Warped, immensely powerful giants with a fierce territorial instinct.
This method of trial and error was used to perfect different strains of the FEV, with the overall goal of improving the synthetic organics program. The research was intended to produce effective synthetic organics, but it ground to a halt in March 2224. Despite perfecting two FEV strains, the accumulated radiation damage in test subjects provided an insurmountable barrier to further development. Just three years later, in 2227, the organic synth project experienced a breakthrough due to the acquisition of Shaun and his undamaged pre-War genetic code. The third generation synth project was spun off from the FEV research initiative.
The FEV research effort continued for several more decades, despite producing no useful data, except for manufacturing more super mutants for the surface to contend with. In April of 2286, Dr. Brian Virgil succeeded Dr. Syverson as head of the project, and it quickly became evident to him that the FEV program had run its course, having produced no new data within the past ten years. As Virgil's conscience took its toll, the scientist lodged a formal complaint with the directorate. When no reaction came, Virgil rebelled and escaped the Institute after destroying as much of the project as he could, which became known as "Incident V" within the Institute. He then proceeded to transform himself into a super mutant using a unique strain of FEV to flee into the Glowing Sea. The FEV program was finally ended after over one hundred years of abduction and experimentation. At the time of the Sole Survivor's arrival at the Institute, the research wing remains in a security lockdown.
“You humans made us - now suffer for your arrogance!”— Super Mutant battle cry
Their mouths are depicted as being closed much like Marcus, unlike the super mutants which carry a permanent snarl. Furthermore, in regards to previous appearances, specifically the Super mutant (Fallout 3)s, these super mutants are smaller, standing 7 feet (2.13 m) tall, have a darker skin tone and appear more scrawny and with less pronounced muscles. The biggest institute super mutants are the behemoths who stand approximately 13 feet (4 m) tall.
The existence of the behemoths suggests a link with the Vault 87 strain of FEV, as they are the only super mutants known to continue growing with age. However, the green-brown coloration is closer to that of the Mariposa strain of FEV, specifically resembling the super mutants seen in Fallout: New Vegas. Institute behemoths differ from those seen in the Capital Wasteland by muscle growth specific to the right arm and a spinal formation that results in an uneven stance. The intelligence of Institute behemoths seems to be higher than their Capital Wasteland cousins as in the specific case of Grun, a behemoth who successfully led a small army of super mutants from the Commonwealth and to The Island.
Unlike their counterparts from the Capital Wasteland, the Commonwealth mutants possess a relatively advanced understanding of armor, weapons and at least some minor knowledge of craftsmanship compared to their brethren. They appear to trade stronger physiques for the intelligence necessary to create and utilize weapons and armor, and even have access to reprogrammed security systems such as searchlights and automated turrets, not unlike their far-western cousins.
Higher-ranking super mutants show more intelligence than their brethren, speaking more eloquently, and utilizing some advanced tactics such as cover, shifting position and taking the high ground. They also are capable of following a chain of command, setting up traps and ambushes, and using human captives as bait. Their lesser brothers, however, will often ignore cover and simply try to get as close to an enemy as possible, even when armed with long-range weaponry.
While predominantly hostile to humans, like their counterparts in the Capital Wasteland, they do retain some capacity to coexist with humans; Strong and Erickson are prime examples of Institute super mutants attempting to integrate to human society, and even hostile mutant groups have been known to keep human prisoners as slaves or entertainment rather than simply killing them.
Like their Vault 87 brethren, Institute super mutants seem to comprehend on some level the possibility of their extinction and express an interest in locating FEV, or "green stuff," to produce more mutants and stave off this possibility.
Super mutants can randomly be encountered around the Commonwealth in small groups, usually raiding parties, which can attack settlements allied with the player character. Much larger groups can be found infesting various buildings throughout the wastes. They have developed a unique relationship with mutant hounds and will utilize these beastly creatures as attack dogs, usually encountered in groups of 1-3. Mutant hounds are exclusively used by super mutants in the Commonwealth, instead of the centaurs that have normally accompanied them in past installments of the game series.
This is the most common and weakest variety of super mutant. They usually carry a pipe weapon or a board and drop minor and low-tech loot on death. They can usually be taken down with minimal effort. They can often be found among more powerful varieties of super mutant such as a skirmisher.
A super mutant that will run at its enemy with a beeping mini nuke in its arm. It will then detonate itself while in close proximity, killing its enemy and itself in a fiery, nuclear explosion. Shooting the mini nuke in the suicider's hand or targeting the right arm in V.A.T.S. will cause the mutant to explode prematurely, killing it instantly. As a result, shooting the bomb from afar is one of the most effective ways to dispatch them, and potentially other nearby enemies as well. If one is desperate to kill a suicider and the only weapon types available are unarmed and/or melee, the player may either sneak attack it, or run to it, strike it, step back a bit and repeat until it's dead (though the latter is not advised as one missed attack will allow the suicider to detonate the mini nuke, and accidentally hitting the mini nuke with either type of attack will detonate it). The suicider can be detected before it is seen by listening for the beeping of its mini nuke. If the suicider is killed without detonating the payload, which can be done with a headshot or body shot, a mini nuke can be looted from its corpse; otherwise, only nuclear material will be found on its remains.
Utilizing the Blitz perk, it is possible to kill the suicider in V.A.T.S. with a melee weapon before it explodes, even if it takes several hits.
Super mutant skirmishers are significantly tougher than regular super mutants, taking more damage and usually carrying more powerful weapons. Skirmishers will appear more frequently once the Sole Survivor reaches level 10.
Super mutant brutes are a significant step up from skirmishers. Brutes, much like their namesake, take even more damage to put down and are far stronger than their lower-leveled brothers, and is wearing an aviator hat of some kind.
A force to be reckoned with, super mutant masters have an extremely high Hit Point pool and superior Damage Resistance compared to their weaker brethren. They are generally equipped with heavy weapons such as the missile launcher or minigun. They can be generally found in locations with a large mutant concentration, an example being Big John's Salvage.
The primus spawns at level 45+ and is seen with large groups of super mutants, most commonly at major super mutant outposts. They commonly wield super sledges or assault rifles, but may also be seen with missile launchers and, rarely, Fat Man launchers.
The warlord is the most powerful super mutant variant. Their extremely high Hit Point total means that they can withstand multiple head or limb shots from extremely powerful weapons like Gauss rifles without being crippled.
Behemoths are the most powerful super mutants by far, towering above any player character, at about 13 feet (4 m) tall. These super mutants are the oldest and strongest of their kind and are many times larger than any other humanoid creature, almost as large as a mirelurk queen. Unlike regular super mutants, they will not speak; instead, they will make monstrous roars. They are armed with a fire hydrant mounted on a large pipe. Other than that, they have the ability to throw heavy boulders at their enemies. Either way, both weapons are heavy hitters and will cause major damage against any enemy smaller than them. They carry a cage made from shopping carts on their back, similarly to their Vault 87 counterparts, which they use to carry boulders that they use during combat.
A behemoth can also be spawned by going to Med-Tek Research and heading north towards Greentop Nursery, where there will be a small vehicle crashed into a group of trees with a Jangles the Moon Monkey sitting inside, which will trigger a behemoth spawn point nearby when picked up.
There is a chance a standard behemoth will spawn around the outskirts of the remains of the institute after beating the game with the Brotherhood of Steel ending.
Multiple behemoths may partake in an assault on The Castle during the repeatable Defend the Castle quest if super mutants comprise the randomly chosen enemy and the player character is at a very high level. There is usually only one behemoth in each wave, but it is possible for two or more to spawn simultaneously.
Behemoths in Fallout 4 can respawn, unlike Fallout 3, where they were unique encounters. The player character can find a unique behemoth named Swan at Swan's Pond, and another unique behemoth in the Far Harbor add-on named Grun at the Vim! Pop factory.
A behemoth can be found in the north section of the map, in a small lake near Dry Rock Gulch.
Glowing behemoths are highly irradiated and can damage enemies with radiation when nearby. Unlike other glowing enemies, this variant appears identical to regular behemoths. Their existence seemingly contradicts super mutants’ established immunity to radiation.
Epic behemoths are an immensely powerful variation of average super mutant behemoths, and, to some extent, are more clever in combat. They tend to appear in forest areas, which they may use to their advantage by hiding behind trees. They also will block their face with their hand quite often, especially when fighting at melee range, allowing for a chance to get in several hits. They are more upright than many standard behemoths in appearance, and although they are quicker, they use similar fighting techniques, such as smashing, knocking the player character down and hurling boulders. Aside from being able to sustain more damage, they can be crippled if low on health and will slump to the ground on their side, where they can be finished off.
If the Sole Survivor manages to shoot a suicider's mini nuke while hidden, it will not affect the detection status, even when the suicider explodes in direct sight of other mutants. They may or may not start to investigate the body for a short period of time.
The mini nukes that super mutant suiciders carry are much larger than the standard mini nuke, appearing more similar to the Mark 28 nuclear bombs used by Liberty Prime and found inside the Sentinel site.
The Sole Survivor can find a semi-educated super mutant named Strong at the top of Trinity Tower. He can be recruited as a companion after completing the quest Curtain Call. Unlike super mutant companions from previous games, Strong is far from civilized, often stating his desire for mutants to kill all humans and mentions wanting "someone to eat" when hungry.
The noise of a suicider's mini nuke is comprised of two parts: a continuous beeping and a tone. This tone is a Shepard tone illusion, wherein the tone sounds like it is continually rising in pitch, but in reality, it is not and is just a loop.
Super mutants have been heard wishing to hunt humans not only for food but for sport, in contrast to their Vault 87 brethren which have only been seen to hunt for food and FEV fodder. While they occasionally kidnap settlers for a ransom of caps, this is likely a fault of radiant quest placement as they don't appear to have any need for conventional human currency, unlike raiders.
Super mutants refer to people in power armor as bucketheads, as they can sometimes be heard saying "Wish a buckethead would show up. I'd rip his legs clean off."
PCPlaystation 4 After detonating a super mutant suicider's mini nuke and killing nearby enemies, no additional XP is gained for these kills. [verified]
PC Upon re-entering a world space where a super mutant suicider detonated, the super mutant may detonate again. [verified]
PCXbox One After looting the mini nuke from a super mutant suicider, it may remain in his hand and may still detonate afterward. [verified]
PC Stunning a super mutant in V.A.T.S. will result in it becoming stuck in a T-pose, unable to do anything but follow its target around while stuck in the pose, with occasional vocalizations from its dialogue options. [verified]
↑Fallout 4 loading screen hints: "The Minutemen first rose to prominence in the year 2180, when they defended Diamond City against a horde of Super Mutant attackers."
↑The Sole Survivor: "Do you remember Edgar Swann?" Brian Virgil: "Swann? ...Yes, I saw his file. He was one of our first test subjects, years ago. His mutations destabilized. Started turning into a Behemoth....You think that could happen to me? Maybe I'm fine for a few months, a few years, but... god. I couldn't live like that." (Brian Virgil's dialogue)