Alicia Huberman
A young woman of German descent, whose father is convicted of treason by the U.S. courts for his Nazi sympathies, Alicia is the protagonist of the film. Unlike her father, Alicia is an American patriot who feels a strong connection to her country, which makes her agree to work as a spy for Prescott and Devlin. She is ashamed of her father and disgusted by Naziism, and as a result she has become a heavy drinker and woman of loose morals. It is also implied that Alicia has been somewhat promiscuous; her love for Devlin leads her to change her ways. She has a strong conscience and she is brave and intelligent, qualities which make her a skillful spy, in spite of her early hesitations.
Devlin
A CIA agent who wants to recruit Alicia as a secret agent. Devlin is a markedly cold individual who rarely shows his cards and seems to operate under the assumption that the best offense is a good defense. He is emotionally imperturbable and always seems to be in possession of himself, which makes him an excellent spy, but not a particularly effusive lover. For much of the film, he is emotionally repressive and unresponsive to Alicia’s advances, which shatters her self-confidence. A bitterly sarcastic man, Devlin eventually becomes concerned for Alicia's well being and runs to her rescue when she is on the brink of death, saving the day and protecting her from the diabolical plot of Sebastian.
Alex Sebastian
An extremely wealthy German expatriate and Nazi, who is also an insecure and jealous romantic. He lives in a lavish mansion in Rio, where he hosts meetings with prominent Nazis. An aristocratic gentleman, Sebastian hides his deeply evil ways under a performance of elegance and etiquette. His polished and chivalrous manner contrasts with his capacities for violence, impulses that are encouraged by his overbearing mother. Despite his wealth and general cold-bloodedness, Sebastian is jealous of Devlin’s doting on his wife, and feels insecure about Alicia's attraction to him.
Madame Sebastian
Madame Sebastian is Alexander Sebastian's formidable, calculating, and remorseless mother. Madame Sebastian is extremely jealous of Alicia's sway over Sebastian, and pursues power by whatever means she can. Indeed, her proposal to poison Alicia is motivated not only by her wish to protect her son, but also her secret desire to be rid of her rival. Madame Sebastian is stone-faced and evil, asserting her dominance whenever possible.
Paul Prescott
Devlin's superior, Prescott is a kind and straightforward leader. He takes care of Alicia and encourages her in her job as a spy, but is generally unaware of what is actually taking place over at Sebastian's mansion. When Devlin visits him at his apartment, Prescott is eating a pastry while lying down in bed. This seems meant to communicate that while he is very comfortable sending others to do his dirty work, he is a man who knows how to relax, even when the pressure is on.
Dr. Anderson
The Nazi doctor with whom Sebastian works. When Prescott discusses sending Alicia into Sebastian's home, he is particularly interested in learning more about Dr. Anderson's role in the Nazi's plot.
Eric Mathis
One of Sebastian's Nazi cohort, a man quick to anger and willing to kill. He is the one who decides that Emil Hupka must be killed, and he's also the man who does it. We also learn that he does not like Sebastian very much. Mathis is competent and completely devoid of remorse.
Emil Hupka
A Nazi who is killed for being indiscreet about pointing out one of the wine bottles filled with uranium ore at the first dinner party that Alicia attends at Sebastian's house.
