Rhoda Despard (née Dawes) is the wife of Colonel John Despard. She is a cousin of Mark Easterbrook. She is a lively, direct, and polite young woman, from a wealthy background. She is described as being "tall, dark and vigorous-looking".
It is likely that Rhoda comes from Devonshire, as she gets Devonshire cream sent to her occasionally, and says that it reminds her of home. She also has an aunt, Emily Deering, who lives in Devon.
During the events of Cards on the Table, she shared a cottage with Anne Meredith. After Rhoda's father got remarried, she was looking for a cottage, and asked Anne to share it with her. At some point before the events of the novel, they had been to Switzerland, where they had met Mr Shaitana. After Mr Shaitana's death, Anne shows distress at any reminder of the incident, but Rhoda thinks it has an exciting side.
Rhoda is an admirer of Ariadne Oliver's work. She visits Mrs Oliver at her home, and has tea with her. Rhoda finds it exciting to be sharing an intimate meal with a celebrity. She also tells Mrs Oliver that Anne had once been in a house where a woman took poison in mistake for something else, and died. Before Rhoda leaves, Mrs Oliver gives her a signed copy of one of her books, The Affair of the Second Goldfish.
When Poirot asks Anne to call on him, she is reluctant to go. However, Rhoda persuades her to go, saying that it will be fun, and accompanies her. Poirot gives Rhoda a treat by showing her a knife, with which twelve people once stabbed a man, and which was given to him by the Compagnie Internationale des Wagons Lits.
Towards the end of the novel, Rhoda and Anne go out on the river together. Anne deliberately causes a rowing accident, to try to get rid of Rhoda. She wanted to prevent Rhoda from telling anyone about Mrs Benson, the lady who had died after taking poison by mistake. She also saw Rhoda as a rival for the affections of Major Despard. However, Major Despard witnesses the accident, and saves Rhoda.
Rhoda reappears in The Pale Horse. This novel was written and set in the 1960s so presumably Rhoda is much older. She is married to the now Colonel John Despard and they have settled in the village of Much Deeping. Rhoda is a cousin of the main protagonist of the story, Mark Easterbrook. At the beginning of the story, Rhoda, who is organising a village fete writes to Mark to ask him to ask his friend Ariadne Oliver to support the event by signing copies of her books. She later sets Mark off on his investigation into some strange deaths he had come across in London by introducing him and Ariadne to three witches living in a house which was formerly an inn named "The Pale Horse".
In the film adaptation of Cards on the Table in Series 10 of ITV's Agatha Christie's Poirot drama series, Rhoda Dawes is portrayed by Honeysuckle Weeks. Her backstory and role in the plot is considerably altered, with an almost complete reversal of roles vis-a-vis her friend Anne Meredith. See the section here for details.
In Cartes sur table, the French adaptation for the series Les Petits Meurtres d'Agatha Christie, the parallel of Rhoda Dawes is actually the main protagonist Alice Avril herself. Like Rhoda in the original, she is almost killed by Elise Schlumberger, the Anne Meredith parallel, except that here it is not drowning but poison. Also Alice pairs off at the end with Paul Coupet, the Despard parallel, although only for a week.