Originally created before the Great War by the government to replace human troops in battle, deathclaws were derived from mixed animal stock, primarily from the very popular Jackson Chameleon. They were then refined by the Master, using genetic manipulation and the Forced Evolutionary Virus. The resulting creature is incredibly fast and powerful.
Around 2161, deathclaws were still considered mysterious and legendary creatures to many. They could originally only be found in the Boneyard at the warehouse, living with their mother. Later, as the deathclaw population grew and began to spread across the continent, the deathclaws stopped being perceived as legendary beasts, and started to be seen just as another dangerous creature.
Deathclaws are tough and formidable melee combatants. Their appearance is also more detailed compared to their Fallout 3 and New Vegas predecessors; they have darker, scaled skin, longer horns (which seem to curve more downward rather than upward), shorter claws and a more draconic/reptilian head and face. Close inspection of their feet will reveal what appears to be a single enlarged toe claw on each foot, similar to prehistoric raptors. The Massachusetts deathclaws are more physically dynamic; showing abilities such as running on all fours when in combat or climbing obstacles, behaviors never seen in the deathclaws of previous titles. Deathclaws can be found anywhere in the Commonwealth, but appear more frequently in the Glowing Sea. When observed from a distance, deathclaws can be seen to throw dirt over what could possibly be egg clutches. They're also known to perch atop hills, rock outcroppings, and boulders surveying the landscape.
Deathclaws are the results of a pre-War experiment that involved creating a mutation of the Jackson's chameleon, along with several other species, to use as weapons on the battlefield. They are strong, agile predators that will attack the player character on sight. Their long, sharp claws are capable of inflicting great amounts of damage on the player character, oftentimes deadly (hence their name).
Deathclaws have a very high amount of health for creatures of their level and are incredibly resistant to most damage types, particularly energy damage. Their versatile combat style makes them a hefty opponent even if they are lower level. When aggravated, they will initiate combat by roaring and stomping the ground, causing a shockwave.
While they predominantly use their namesake claws for dealing damage, they may also headbutt their foes to stagger them. Their power attack comes in the form of a wide-swinging claw slash which deals significant damage. If one is available, they have also been noted to use both hands to throw cars at an opponent who is out of melee distance.
Deathclaws have the ability to instantly kill the Sole Survivor or other humanoids, either by grabbing and smashing them into the ground, or decapitation with its claws. This maneuver only occurs when the Sole Survivor has low enough health, although this is relative - higher percentages of health at low level can still result in the instant-kill attack, but at higher levels it may not occur until the player has very low health. Other times, the deathclaw may pick up the player and slam them into the ground forcibly, causing moderate damage. The instant kill can also be nullified by wearing any type of power armor. Instead, the deathclaw will grab the Sole Survivor and stagger them, draining their AP completely. A deathclaw will also toss sand into the air to provide a brief distraction.
The deathclaws have a substantial level of natural armor and are resistant to damage on their dark, scaled parts, leaving the belly as a weak spot which takes increased damage. However, due to their hunched posture, this is difficult to hit. Although the Penetrator perk allows the Sole Survivor to hit the deathclaw anywhere while using the Vault-Tec Assisted Targeting System, this works by shooting through the deathclaw like it is a solid object. They can dodge gunshots and zigzag while charging the shooter, making them even harder to hit. If one of their legs become crippled, broken bone will be seen stabbing out of the skin, and they will move incredibly slowly. With both legs crippled it is unable to move at all. It is also possible to shoot off the end of their tail.
Their model size makes them ungainly in uneven ground, which can be used against them. Their inability to climb or jump (aside from scripted events such as in Concord) renders their close-combat style useless if attacked from high enough ground, and if they are unable to travel certain terrain such as jumping up on a rock, they will flee until their target is on level ground again. Many of their attacks can also be avoided by keeping a constant pace, which allows the player to simply outrun their claw strikes.
The variants that can be encountered are based on level. Different variations become increasingly more common with higher levels. For example, where one might expect to encounter a normal deathclaw, they might encounter an alpha deathclaw once they pass a certain level. The higher the player's level, the more chance of the next difficulty of deathclaw to spawn in its place. Scripted encounters, such as on top of Haymarket Mall and at Lynn Woods, have a higher chance of spawning a next-stage deathclaw than randomly encountered wasteland ones.
Normal deathclaws, defaulted to level 22, are highly dangerous for those poorly leveled and still present a challenge at higher levels. Deathclaws will charge the target while defending their weak belly with their head, making it difficult to land a shot to the weak spot even in V.A.T.S.
An Alpha deathclaw can be encountered by flipping the breaker at the top of the tower in Lynn Woods and the roof of Haymarket Mall (two may spawn on the roof). They may also be encountered in the Glowing Sea and west of Natick Banks. Alpha deathclaws have horns that spread foward and up, while a regular deathclaw is forward and down. Alpha deathclaws also have rust-colored skin.
The glowing deathclaw is a highly irradiated version of the standard deathclaw. A green light emits from the skin between their scales, and they inflict radiation damage on top of their massive ballistic damage. They can start spawning in as low as level 25, replacing several randomly-encountered deathclaws including those above Haymarket Mall and Robotics Pioneer Park.
For unknown reasons Quantum deathclaws were cut from Nuka-World. These deathclaws were mutated in the same way the Nukalurks were. They resemble glowing deathclaws, but with a blue-purple glow instead of green.
Matriarchs have less health than an alpha, but more than a normal deathclaw. Their horns curve out and down, compared to the alpha's forward and up. They start to appear when the player is around level 35, and will replace some randomly encountered deathclaws in the wasteland.
A scripted savage deathclaw may be found in the Museum of Witchcraft. This event is leveled and part of a side mission. The Sole Survivor can choose to fight but can also run away or sneak through it. If the player has a high enough level, they may encounter savage deathclaws in random encounters, such as within the Glowing Sea or near Natick Banks. A savage deathclaw is probably a deathclaw matriarch with a broken horn. This can be proven by both of them having the same color skin, the yellow lines on their body and the spread out horn.
The albino deathclaw is a pale version of the deathclaw, with more health, that can be encountered after reaching level 71. This deathclaw type's high health can make it a worthy adversary and it will only lose 1/4 of its health from a shot from the mysterious stranger.
The chameleon deathclaw will begin to spawn at Level 81. Its default color is a slightly more sandy tone of a regular deathclaw, but when aggravated, it will display vibrant colors depending on its movements in battle. It flickers between stone gray, acid green, red, orange and teal. When killed, its body retains the last color it was displaying.
Mythic deathclaws are the highest non-legendary tier of all deathclaw variants and can be encountered starting from level 91. On rare occasions, they can be encountered from level 75. These level with the player, so they are immune to the Wasteland Whisperer perk.
A leveled deathclaw is scripted to appear at Garden Terrace on the roof of Haymarket Mall (sometimes a bug will occur preventing the deathclaw from jumping onto the terrace, so it will remain glitched onto the side of the mall, until the player attacks it).
Two random encounters can be triggered by throwing the switch on top of the tower in Lynn Woods. This can be repeated every few days once the area has respawned.
One can be found guarding the entrance to Old Gullet sinkhole. It is passive until it detects you when you first encounter it; once killed, respawns will often be permanently passive until attacked.
A scripted deathclaw can be encountered at the bottom level of the Kendall Hospital.
Two deathclaws can be found west of Natick Banks, by a few satellite dishes, fighting a behemoth. A leveled deathclaw can be found lurking around an abandoned garage with a tanker on the side of the building, a normal deathclaw can be found on the farm just up the road from the Matriarch, and one or two leveled deathclaws may be found around the church, fighting a group of leveled super mutants (depending on if the mutants were killed, prior to the player's arrival)
One can be found in the Robotics Pioneer Park, inside the first house from the fast travel point. Like the Gullet Sinkhole deathclaw, there is a chance that consequent respawns will be passive towards the player until attacked.
One can be found east of The Slog near a bus on the overhead road. You can see it from the snack bar if you look towards the road to the east at the bus. It will come down and through the water towards you if you shoot at it.
One can be found in a rock formation close to Coastal cottage, wandering around a couple of yao guai corpses.
Two deathclaws may be found in the bus stop, west-southwest of the Galactic Zone in Nuka-World. One will be patrolling the area, while the second will spawn when the Sole Survivor enters the middle of the area. The second deathclaw will be a higher level spawn.
There is a permanent deathclaw nest on the southwest side of the tarn due south of the federal ration stockpile and it usually has a non-pristine egg. The nest contents respawn at least once for certain and may continue to do so if looted. The nest owner may or may not be around. Other nests can spawn occasionally but are random. one such location is southwest of Forest Grove marsh. These are independent of "the Devil's Due" nest which requires the pristine egg.
In the quest The Devil's Due when returning the egg, the deathclaw guarding the nest is scripted to be permanently friendly to the player and their followers as long as the nest is not interacted with after the egg is returned.
It is possible to shoot the tail off of a living deathclaw. Likewise, it is possible for an alpha deathclaw with no tail to spawn by the Lynn Woods siren.
It is possible to encounter and possibly tame a mythic deathclaw as early as level 16, through the deathclaw cage in the Wasteland Workshop add-on.
The sound effect used for a deathclaw's claw strikes is identical to that of werewolves from The Elder Scrolls V: Skyrim, Bethesda Game Studio's fifth entry in their Elder Scrolls series and the last game they developed prior to Fallout 4.
If the Far Harbor and Wasteland Workshop add-ons are both installed, it is possible to build the associated cages to import deathclaws onto the Island.
If a deathclaw takes sufficient damage from an engagement, it will run off and usually come back later. However, this is a new engagement and the deathclaw will run off quicker.