Deconstruction of Characters in Sin City:

Sin City is one of few largely known, well received, contemporary examples of film noir movies, that very firmly sits within the film noir genre. For that reason I believe it will be a good example to deconstruct the characters of.

Marv:

 Marv is one of the male protagonists of the movie, played by Mickey Rourke. He conforms to the following conventions:

• Violent nature/history of violence: This character is often shown with some kind of injury and regularly threatens violence.
• Code of honor: Despite his violent history and difficulty with people, he refuses to hurt innocent people or animals.
• Vengeance: A common convention in film noir is the theme of revenge, justice or punishment. Marv strongly disagrees with harming women, and so deals with anyone guilty of these things with violence.

 Dwight McCarthy:

 

Conventions that Dwight, another male protagonist in the movie, follows:

•  Private investigator: Detectives or private investigators are extremely common for male protagonists in film noir. It gives them a reason to analyse the plot, deconstructing it in their monologue for the viewer to understand better, but also a reason for them to investigate it.
• Extremely cynical/nihilistic: Film noir movies are always set in dark, depressing settings. It could be argued that this is because it is reflective of the highly cynical, pessimistic worldview, but it could also be argued that the character is cynical and nihilistic because of the dark, depressing environment in which the narrative takes place. Regardless, Dwight fits in to this convention, often having a defeatist attitude or being completely unsurprised when something tragic happens.

Goldie and Wendy:

Goldie and Wendy, played by Jaime King, are two of female leads in the film. They conform to the following conventions:

• Prostitute: Goldie and Wendy are prostitutes, and film noir plots often revolve around a woman, sex and lust. 
• Film noir often has a theme of "learning too much" or "ignorance is bliss"; characters often get into trouble or even die for learning too much about the wrong people, or intruding on matters that don't concern them. This is usually the male detective character, but can be others. In this instance it is Goldie, who dies after she learns another character's secret.
• Femme Fatale: Goldie and Wendy are powerful women with a large section of the city under their control. This along with other aspects, such as their involvement with sex, and a tendency to wear red, make them Femme Fatale characters.