A man can be reduced to a mere shell of his former stature.
Though empty, a mere shell of a human being, still his body stumbled on.
He had bought the 1815 house four years previously, when it was a mere shell.
The house threatened to give way at any moment: one end of it was sinking, and, in fact, the building looked a mere shell.
Six months later he was dead, a mere shell of his former self.
It was as if she were a mere shell going through the motions.
I'm guessing that they are both mere shells of what they were.
Without such power and responsibility they are mere shells.
He was then returned to the ship a mere shell of his former person.
Most of the buildings were mere shells, if that much.