A genuinely good man, Mr. Charles Darnay is portrayed as the hero of the novel. Although considered as the main protagonist, he is never really developed by Dickens. Charles is a good guy, through and through. This makes him almost unattainable to the reader because he is hard to connect with, being only good, and possess no bad qualities.
The Perfect Protagonist
Charles Darnay and Sydney Carton look uncannily similar. It is never said what exactly either looks like with regards to hair/eye color and physical stature. This leaves the imagination to the reader and focuses our attention to the character of the person rather than stopping at the physical features.