Super Mutants is a faction in Fallout: New California
Super mutants were first created on the West Coast by Richard Grey, also known as "The Master". He decided that he would have to force humanity to evolve beyond its innately destructive tendencies by turning them into super mutants. In 2162, a person known to history only as the Vault Dweller destroyed the Master's mutant army by causing an explosion in the FEV vats at Mariposa, which collapsed the entire base, after which he proceeded to The Cathedral in the ruins of Los Angeles and killed the Master.
In 2236, the Enclave discovered the remnants of the Mariposa Base. Soon, Enclave assault squads combed the desert for slaves they could use to excavate the military base and get to the FEV vats. In 2237 the Enclave abandoned the site after mutations occurred among Enclave personnel and slaves exposed to the FEV remnants in the facility, causing a second generation of Mariposa super mutants to arise.