Rhoda Penmark is an eight-year-old girl who is charming, polite, and intelligent beyond her years. Beneath her lovable facade, however, she is a sociopath (or psychopath) who is willing to harm and even kill anyone to get whatever she wants, whenever she wants it. She is also a precociously talented con artist, adept at manipulating adults. Other children, who can sense her true nature, avoid her. In the beginning of the novel, she brutally murders a classmate and a groundskeeper who suspects her. It is also revealed that she murdered an elderly neighbor and her pet dog a few years before. March writes that Rhoda's evil is genetic: her maternal grandmother, "the incomparable Bessie Denker," was an infamous serial killer who also began killing at Rhoda's age. Rhoda's mother, Christine, was adopted at a very young age and does not remember her biological parents. She was portrayed by Patty McCormack in the original rendition of the play and later in the 1956 film adaptation. She was also portrayed by Carrie Wells in the 1985 made-for-television adaptation and by Mckenna Grace in the 2018 adaptation.