In the final days of World War three, the US Army grew skittish, with the threats of Nuclear attack. They found that they had the very real possibility of being decimated by hundreds of nuclear warheads and then invaded by the Chinese Military. As a result, they opted to put around two hundred, homeland security Soldiers in Cryo Stasis.
In the 2240s, Presper discovered the facility and opted to mutate the US Army Remnants, to serve as her own private army. The strain of FEV affected everyone differently, some became ghouls and some became more like Super Mutants. The only one, who was spared from this fate was Armstrong, who was eventually augmented himself.
They now travel the wastes, on various missions, in a state of inpenitrable delusion. They believe themselves to still be fighting the Great War and genuinely believe that their once great country has fallen to communism. In their minds, they are fighting a difficult to win but worthwhile cause, when in reality, they are thugs for a manipulative mad scientist, who plans to rid the world of their kind, once they have outlived their usefulness.
Presper has set a Biological clock inside each and every one of them, so that they will die out around 2260 as their usefulness will have long since ended by then.
Their culture appears to be somewhat primitive and they have a Hierarchy of sorts. The majority of them are of average human intelligence though there are some that have been dubed "Cleavers" by the locals and even by some of their comrades, that are more savage and as their name implies, they seem to use cleavers a lot.
The similarity to Ghouls is their wrinkled skin, with most of them having grey or tan skin. There are a few that are about the size of Super Mutants but with white-ish gray skin.