Having played through the game, I'm confused by the marauders. At one point we hunt one down who used to be a doctor (?) in Edgewater, so they were obviously part of human communities at some point. They use armor and weapons normally.
But you never get to speak with a marauder and they don't seem to have any back story or true community. A few of the notes and pieces of lore made them sound almost like a zombie plague, descending on the colonies. There was even one note, from a scientist, saying that they couldn't operate key pads!
So are they just down-on-their-luck humans who decided to turn outlaw, or are the marauders somehow sub-human?
Has anyone found an explanation?