 Why did Charles think he was the last person alive?
There should be an epitaph for every man, big or little, but a really grand and special one for Loner Charlie. New York lay quietly below him. To any man, WHO HAPPENED TO BE THE LAST MAN ON EARTH! A month later the meat animals, the birds and the household pets began dropping as rapidly as the flies which had dropped earlier. Within a year it was obvious to everyone that man was the only animal left on earth. Within six months, half of the world's population was gone. Less than a month ago no more than a few thousand people remained in New York. And now.... "I've got to find out," Charles told himself.
 He had some sort of immunity
 His sickness was taking longer  He had some sort of immunity  He was the reason for the plague  He was meant for greater things