The Institute mutants don't have a story of struggle like the other two groups, but most of their forces are scattered across the northeast and they aren't quite as united as the vault and mariposa mutants.

Those ghouls warned of this invasion and a majority of mutants retreated out of the Capital and made their way west where they met the Mariposa race. Eventually the BoS caught wind of the increased presence by the vault and planned an invasion. A group of ghouls despised the Brotherhood of Steel and turned to Vault 87 for help.

The vault mutants that came from Vault 87 were pushed around by the Brotherhood of Steel and Enclave for too long, however they weren't entirely against all the people in the wasteland. There they remained, kidnapping humans, creating more samples of the FEV, and growing their numbers as they set up camps and settlements. All across the western US mutants migrated East, until they settled in Ohio in 2277. Unfortunately after the battle of Hoover Dam the victor started a massacre, killing off both hostile and the more peaceful mutants in the region. While some mutants wished to continue their fight against humans and further spread the FEV, many simply settled down in settlements like Jacobstown and Westside. Mutants from California were pushed east, and those from the eastern coast traveled west, bumping into different strains of mutants along the way.

Unfortunately the mutants were outmatched by the armies of the Brotherhood, NCR and other factions that opposed their rule. Many saw themselves as evolved humans, others ditched their 'humanity' and fought their former species. Super mutants however, they were different. War.war never changes, a belief that the premise of war shall never change due to humanity's lust for power, and for the differences found between races, religions, and cultures.

Fallout 1 super mutant invasion