Lepers

Official Description
"Often confused with zombies, these unlucky creatures are descendants of unfortunate survivors of nuclear fallout, whose DNA, damaged by radiation and passed on to next generations, over decades of inhabiting heavily irradiated zones resulted in "evolution" of a degenerate, foul new type of savage cannibals. Impaired regeneration of skin tissue and other radiation-induced malformations, being their most characteristic trait, led them to be referred to as "Lepers". Mostly isolated from the human society, they form caveman-like, nomadic communities focused on searching for food, some of them however are able to communicate the same way humans do, or even side with certain factions and - to a certain extent - blend into human environment despite strong prejudice."

Trivia

 * Lepers are either barbaric in nature, or civilized.
 * It is suggested that Lepers could be in official factions.