Hermann Karlovich
This German Russian businessman owns a chocolate factory. One day, he encounters a man who appears to be just like him. The homeless man, Felix, disagrees, but they meet anyway. Karlovich does not really respect his wife very much, but it is all the same with her, because she is cheating on him. Hermann is onto her after seeing a peak of her and Ardalion together, but he denies the affair to himself. He is interested in murdering his doppelgänger to collect his life insurance money.
Lydia
Lydia is Hermann's wife. From his point of view, she is described as a bit of a ditz, and Hermann does not really respect her. She is in an affair with her own first cousin, a man named Ardalion. She has a playful, flirtatious relationship with Ardalion, but one day she becomes too careless and she is silently discovered by her husband. The husband is so convinced that Lydia worships him that she gets away with the affair.
Ardalion
Ardalion is a minor character in the story. He is Lydia's first cousin, and because he is family, Hermann is not suspicious about him spending long stretches of time with Lydia. However, secretly, Ardalion and Lydia are having affair. He stays over at the Karlovich house often, and when the husband goes to work, Ardalion and Lydia have their little escapades. One time, Karlovich found Ardalion naked in bed with his wife, but Ardalion never learns about that.
Felix
The major action of the novel, surprisingly, is not the affair. Hermann meets a man who looks just like him, he alleges. Of course, that is still up for debate, because Felix himself says he really does not see the resemblance whatsoever. When Hermann murders Felix to claim the life insurance money on his own life, the police quickly catch him, because Felix was right. They do not really look that much alike. This is simply evidence of Hermann's misguided perception.
