The idea for the Unity was first formed by scientist Doctor Richard Grey (formerly Richard Moreau) who was exposed to F.E.V. for a long period of time and it eventually mutated him into The Master; a hungry fleshy blob that could absorb the minds of other creatures.
The Master believed that the human civilisation was doomed to crumble and that the only way to save it, was to make everyone in the world "equal" by dipping them into vats of the F.E.V. and transform them into what The Master believed to be the next step in human evolution, Super Mutants.
In order to make the Unity a reality, The Master created his own Super Mutant army to track down humans, particularly ones in vaults, to create more of their own until the Super Mutants are left as the most dominant species on the planet. However, as a result of the Great War, many humans living in the wasteland have already been exposed to a mutated form of the F.E.V. that inoculates them from feeling the full effects of the original strain of the drug.
Many human wastelands who have been dipped in the vats either become Super Mutants with low intelligence or die a horribly painful death, and if the survivors are not fit to join The Master's army, then they are devoured by The Master himself.
However, humans who have spend their lives in a vault have been the least exposed to the mutant F.E.V. and therefore would be effected the most by the original F.E.V. strain, making them much more sought after by The Master's forces.
In order to help gather more humans for his cause, The Master allowed a cult named the Children of the Cathedral to help spread his beliefs and philosophies while also using it as a cover to hide his activities.
Eventually, a traveling Vault Dweller put an end to The Master and his vision of unity. However, even if The Master had succeeded in his plans to convert all of humanity into Super Mutants, a problem concerning Super Mutant reproduction would have stopped any long-term hopes for a golden age.