Though information is given about British Secret Service Agent James Bond's past, Casino Royale paints a good picture of the man in the present. Dark-haired and blue-eyed, Bond has worked in the service long enough to earn him the distinction of a Double O, the highest rank to which an agent can rise. While others think him a hero, he views his rank for what it actually means: he killed two men in cold blood on the orders of his superiors. A trained assassin and spy, Bond is known for his dedication to his work and his harsh, straightforward manner. Often called "heartless" by his coworkers, Bond has little interest in personal or romantic relationships, all of which, in his experience, inevitably end. Women have little value to him outside of their looks and their ability to serve as sexual partners, and he dislikes anything considered to be feminine, including decorations and emotions. A misogynist to his core, Bond seems to believe a woman's place is in the home, not in the office, and certainly not in the field. He prides himself on his masculinity and his clear-cut morals. When he is forced to question these, the uncertainty sends him into an existential tailspin and prompts an unheard-of decision: to give up his career and pursue a long-term relationship. These changes don't last for long—when evil makes itself known, he returns to his former self.
Dark-haired and devoid of cosmetics, Vesper Lynd (a reference to evening prayers) catches James Bond's attention for her appearance and self-confident demeanor, not her skill in the field. Assigned to Bond's mission by the Head of S., Vesper seems to bring more trouble than assistance to the operation. That's because she's actually a double agent working for the Soviets. She's loyal to them until she sees the damage Le Chiffre inflicts on Bond, which prompts her to try to disentangle herself from the Reds. She appears to truly love Bond, so much so she commits suicide in an attempt to keep him safe.
Cold, calculating, and boasting a brutal temper, Le Chiffre is James Bond's target in Casino Royale. Desperate to pay back the money he took from the trade union, he goes to great lengths to ensure Bond won't walk away from the baccarat table alive. When those attempts fail, he tries to torture Bond out of his winnings. Little is known about Le Chiffre's past and personal life. His true identity is a mystery, though it is known he was an inmate at Dachau concentration camp before adopting his new name, which roughly translates to "number" in several languages. He is ultimately killed by an agent of SMERSH for his trespasses against the Soviet government.
René Mathis loves his job. As an agent for the French Secret Service, he takes absolute delight in the twists and turns that accompany covert intelligence operations, particularly when they allow him to get more involved and play a role in the final takedown of the enemy. Far less serious than Bond, Mathis approaches his job from the standpoint of one trying to protect his friends and family from those who wish to spread evil and discord around the world. He doesn't spend time worrying about who's right or who's wrong—he goes with his gut and protects those he cares about most.
Felix Leiter offers to provide backup against Le Chiffre and his henchmen. When Bond loses his entire bankroll in the baccarat game Leiter saves him by providing 32 million francs (approximately $843,548 at the time) so he can continue playing. Leiter's reference to "Marshall Aid" alludes to the American Marshall Plan—a major provision of financial aid that helped European countries rebuild after World War II.