The dark knight, your thoughts?

You see,after Harvey Dent dies after batman pushed him off a ledge,after he threatened to kill jim gordons son.Batman realized that gotham can't know what Harvey dent has done.So he tells jim gordon to tell the police that he is responsible for the murders.Now batman is a fugitive in gotham.As the movie ends,Jim Gordon tells about batman.He breaks the batsignal,and the police try to find batman.Jim Gordon Tells the audience that batman is'nt a hero,but a guardian of the city,He is,a Dark knight.And then the credits roll in.So the reason that he's called the Dark knight.