Revenge

Marv's motivation throughout the graphic novel is revenge. He doesn't just want to remove evil people from the world. He wants to make them suffer for what they've done. In Sin City, where the police and the people behind them, like the powerful Roarks, are corrupt, there is no substitute for brute revenge. There is no justice. The problem with revenge, for Marv, is that it ruins him as well as the evildoer. Marv himself is damned by the vengeance he takes out on others. He ends up in the electric chair, and he believes he deserves to be there. More than that, Marv believes that the people he's killed are in hell, the ultimate revenge against them for their sins. Marv also believes that he, himself, is going to hell, where the revenge against his soul will be complete.

Although Marv wants revenge against the people responsible...