Unity crisis The Unity crisis was the rise of the Master and his army , with an ultimate goal of converting all of humanity into Super Mutants . Origins of the Unity . Richard Moreau was a resident of Vault 8 , later known as Vault City , where he worked as a doctor . In 2092 , he was exiled from the city . He changed his name to Richard Grey and headed south , eventually settling in the Hub , where he met Harold , a prominent trader . Following ever increasing attacks on Harold ' s caravans by mutated creatures , the pair teamed up on May 22 , 2102 , and led a team of scientists who mounted an expedition to the northwest to investigate the source of the mutated animals , which were attacking the survivors of the war . On June 23 , 2102 , Grey and his party stumbled upon the Mariposa Military Base , in which the U . S . government had been mass producing and experimenting with the Forced Evolutionary Virus ( F . E . V . ) . With the exception of Grey and Harold , the party was cut down by the mutated creatures and the base ' s internal defense systems . Harold barely escaped , but Grey was plunged into a vat of F . E . V . by a robotic arm . Floating in the vats for almost a month , the F . E . V . transformed Grey into the amorphous , blob - like being that would eventually become known as the Master . This entity expanded its biological mass by absorbing other creatures and people that came near the base , and bionically merging itself with computer equipment from the base . The ones he consumed also became part of his multiple personalities . It also began capturing humans that stumbled upon its lair , and intentionally exposing them to the F . E . V . These initial mutated humans were incredibly flawed , and the newly named Master consumed them rather than letting them live . As he began to feel stronger and more capable than ever before , he came up with the idea to ' unify ' the wasteland , to make it as perfect as he believed himself to be . In January of 2103 , the Master perfected his method of infecting , or ' dipping ' , humans , and began creating the super mutants , who followed the Master ' s every command . Unfortunately for him , as he began to dip others in the vats he found the resulting creatures were not like himself : most often , they mutated into brutish soldiers , losing much of their brain function . It became apparent that only those with low total radiation count would not suffer this fate . Crisis . In 2130 , the Great Winter occurred , causing a scarcity of human subjects for dipping ; therefore making it difficult for the Master to expand his army further . From 2131 to 2135 , the Master started to abduct caravans for human subjects . Most of the caravan disappearances were blamed on desert monsters , steering away suspicion . Starting in 2137 , the Master began to mass produce super mutants with 1 in 6 being successful super mutants , and only this sixth making it into the Unity . Around 2151 , the mutants destroyed the Union of Atomic Workers . From there , the Master ' s Army mobilized and slowly began a conquest of the Core Region . In 2152 , as the influence of the Master ' s army began to spread throughout the wastes , the Master came into contact with a group of human Doomsday cultists , led by a man named Morpheus . Realizing the benefits of retaining unaltered humans in his service to act as spies throughout the region , the Master recruited Morpheus ' s cult into his service , thereby expanding his power . Vault Invasions and the Rise of the Cathedral . The Master , having discovered that pure strain humans had better chances of retaining their intelligence and strength upon being mutated by the FEV virus , began a conquest for humans without radiation exposure . He quickly determined the best source of pure human stock : the vaults . Vault 17 was raided in 2154 by the Master ' s Army , and its inhabitants were taken prisoner and subsequently turned into super mutants . In 2155 , the Master discovered the location of an unnumbered experimental Vault - Tec vault prototype , located just south of the center of the ruins of Los Angeles , California , now called the Boneyard . Seeing great opportunity there , the Master relocated to the vault with his human cult followers and a portion of his ever - growing super mutant army , and oversaw the building of a large cathedral on the surface above the vault the following year . The cult became known as the Children of the Cathedral , and continued to be led by Morpheus , who reported directly to the Master . The Cathedral was guarded by the nightkin , which were super mutant elite troops equipped with Stealth Boy technology . In 2157 , the Master learned the location of Bakersfield ' s Vault 12 , and in order to further his plans , he sent a detachment of super mutants there to seize the Vault . Many ghouls were snapped like twigs in the attack , until Set , leader of Necropolis , finally parleyed with the super mutants , telling them that the ghouls were the vault dwellers the super mutants were looking for . The super mutants , angered at failing to find an intact Vault , set up a small garrison at the watershed to watch the inhabitants and ensure Set ' s cooperation in the further advancement of the Master ' s dream . Growing Opposition . Few stood up to the Unity , because the existing factions in the wasteland at the time didn ' t possess the power , knowledge or resources to fight off the threat to humanity . Many weren ' t even aware that the mutants existed . Around 2161 , the Followers of the Apocalypse were one of the few groups to suspect that the Children of the Cathedral had ulterior motives . Despite their claims of having peaceful intentions , the emergence of the Children coincided with a sudden surge of unexplained disappearances , especially of those who objected to their cause . Talius , a ghoul - like mutant partially exposed to FEV by the Master ' s forces , found refuge among the Followers , and helped them understand the true nature of the Children and the " Dark God " they served . Although pacifists by nature , the Followers were determined to stop the Master ' s plans by any means necessary , even if it meant resorting to armed conflict . They began secretly gathering intelligence on the organization that could prove useful in the upcoming showdown , using one of their members to infiltrate the organization and spy on them . They also provided informational and material support to those who sought the destruction of the Master and the Cathedral . The Brotherhood of Steel only learned of the Super Mutant threat until fairly late into the Unity ' s conquest of the Core Region , and even then did not openly engage the Master ' s Army . Brotherhood patrols sent south towards the Boneyard never returned . High Elder John Maxson expressed a desire to fight the mutant armies , but he and the other four elders couldn ' t come to a consensus . In October of 2161 , a Brotherhood patrol stumbled upon the corpse of a Super Mutant . The remains were transported back to Lost Hills for study by Head Scribe Vree . Because of their knowledge that the mutants wouldn ' t be able to reproduce , Vree recommended to simply let them die off . The Brotherhood didn ' t engage the Master ' s army until the arrival of the Vault Dweller . Entrance of the Vault Dweller . Vault 13 ' s overseer , Jacoren , sent the Vault Dweller out on a mission to find a replacement for the vault ' s broken water chip on December 5 , 2161 . On February 13 , 2162 , the Vault Dweller found the water chip in Vault 12 . When in Necropolis , he engaged the Super Mutant garrison that was set up there . One mutant with a flamethrower killed his companion , Ian . Upon returning to Vault 13 , the Overseer told him that the amount of super mutants located in the area did not match up with natural rates of mutation . Believing that someone must be artificially creating the super mutants and fearing for the safety of the vault , he ordered the Vault Dweller to find and destroy the source of the mutants . Death of the Master . The Master ' s Army attacked Necropolis and killed the majority of its inhabitants shortly after the Vault Dweller ' s departure from the city . He was told that the Master ' s Army was looking for him , and that he had become known as an enemy of the Unity . On March 3 , the Vault Dweller successfully infiltrated the Cathedral . The Cathedral was destroyed in an atomic explosion which could have been caused by the Vault Dweller sneakily detonating the nuclear weapon within the demonstration vault , or by the Master himself after being convinced that his plan would fail . The Master also could have been simply killed in combat , with the bomb being detonated as a part of a self destruct sequence . Destruction of Mariposa Military Base . The Vault Dweller soon found Mariposa Military Base . Causing an explosion in the F . E . V . vats on March 24 , he single - handedly destroyed the Lieutenant of the Master ' s army as well as the Unity ' s ability to produce more mutants . Dogmeat was killed during the infiltration of the base , running into a force field and being electrocuted to death . The mutant threat had been abolished . The Unity Crisis was over , but its effects would change and shape the wasteland for years to come . Aftermath . Shortly after the destruction of Mariposa Military Base , most of the survivors of the mutant army fled to the east . Several mutants led their own armies after the fall of the Master . Remnants of the Master ' s army , such as those led by Tabitha , were found to relocate to inhospitable regions such as Black Mountain . However , despite their lacking numbers and remote locale , they were still found to pose a threat to the populace of the Mojave Wasteland due to frequent and brutal attacks carried out against travelers . Gammorin led many mutants into the midwest , where they were pursued by the Brotherhood . This led to the creation of a splinter faction of the Brotherhood and a long , drawn out war between Gammorin ' s Army and the new Midwestern Brotherhod of Steel . Attis led another group down to Texas , seeking to revive the Master ' s dream . In 2236 , Enclave troops stumbled across the old abandoned Mariposa Military Base . The Enclave excavated the military base , largely using a workforce of miners gathered from surrounding locales that eventually found the vats deep inside the lower levels of the base . Though they had been buried in rock and forgotten for decades , the vats still contained the Forced Evolutionary Virus . The Enclave gathered samples to be sent back to their oil rig for further analysis and study . They found that it would be possible to make from FEV an incredibly potent and lethal toxin that only affected humans with even slight radiation exposure . Thus , they generated a plan to launch the poison into the jet stream of their base to kill off the entire known population of the mainland . Interestingly , despite the Vault Dweller playing the largest part in the defeat of the Unity , the New California Republic disregards his canonicity . The tribe of Arroyo did the complete opposite , revering his adventures and viewing the conflict in a very religious light ; a battle of good versus evil . Some super mutants , such as Marcus , still retain their feelings of loyalty to the Master while not necessarily disagreeing with the actions of the Vault Dweller .