Undine Spragg
The protagonist is a young woman from the midwest. She's a precocious young lady who deceives herself as to what she truly desires. Thinking happiness can be bought, she devotes her entire life to trying to marry the man who will give her the most money to spend. She ends up leaving a long train of angry men behind her, often calling them up for more money after the end of their relationships. Despite her shortcomings, Undine is resourceful, tenacious, and charming. She knows how to manipulate a conversation, leaving all parties impressed and satisfied with her performance.
Elmer Moffatt
Undine's first husband eloped with her when they were very young, still living in the Midwest. He quickly divorces her because they are not in agreement about anything. He patiently devotes himself to vocational success, so that decades later Undine returns to re-marry him in order to take advantage of his newly acquired fortune. He's not the kindest or most respectable of men, having not been raised a socialite like her many other husbands, but that's an advantage to them. Both he and Undine find some mutual ground the second time round because they come from similar backgrounds and have the same sense of humor.
Ralph Marvell
Ralph marries Undine in New York when she's young. His family used to be highly respected and wealthy, but by the time her marries Undine they're falling out of fashion. Moffatt soon learns that Undine merely wants money, but he's unable to satisfy her. After their son is born, she leaves for Europe. Ralph grows close to little Paul and takes over custody of him after his divorce from Undine. Later, in her attempt to marry Raymond De Chelles, she blackmails him into paying her by threatening to fight for custody of Paul. Ralph knows she doesn't love her son, so he borrows money to pay her, but it's not enough. Distraught, he eventually commits suicide.
Peter Van Degen
While in Europe, Undine has an affair with Peter. He's married to Clare, Marvell's cousin. Although the two have a good time together, Peter is unwilling to marry Undine after she divorces Ralph for him. He will not leave Clare, rightly sensing that Undine is a gold digger.
Raymond De Chelles
Raymond is a French aristocrat. His family is well-established and has old money. Determined to use Raymond as her ticket to wealth, Undine seduces him. He refuses to marry her because his Catholicism prevents him from marrying a divorced woman, but Undine convinces him that she will bribe the Pope to annul her marriage to Ralph Marvell. Ralph kills himself, first, however, so they are allowed to get married as she's now a widower. Their marriage is no more happy than Undine's previous marriages, and she soon divorces him too.
