Quote from : Sin City, Vol. 2: A Dame to Kill For Book

Most people think Marv is crazy, but I don't believe that. I'm no shrink and I'm not saying I've got Marv all figured out or anything, but "crazy" just doesn't explain him. Not to me. Sometimes I think he's retarded, a big, brutal kid who never learned the ground rules about how people are supposed to act around each other. But that doesn't have the right ring to it either. No, it's more like there's nothing wrong with Marv, nothing at all--except that he had the rotten luck of being born at the wrong time in history. He'd have been okay if he'd been born a couple of thousand years ago. He'd be right at home on some ancient battlefield, swinging an ax into somebody's face. Or in a roman arena, taking a sword to other gladiators like him. They'd have tossed him girls like Nancy, back then.