Games and puzzles are a motif in the novel, connecting the plot from the first three books to this book and the sequel series and representing the complicated way families can shape an individual. Jameson, Avery, Zella, Branford, and Catherine participate in the Proprietor’s Game, a series of riddles with a reward at the end. Grayson must crack both his father’s puzzle box and the coded journal to help recover Acacia’s missing funds and protect his sisters. In the Devil’s Mercy, there is a whole gallery dedicated to various betting games, and there are ledgers with wagers in the other rooms. The puzzle motif not only builds the mysterious tone of the novel but also represents how each character is trying to understand how they fit into the larger picture of their families.

Paternal figures are a motif in The Brothers Hawthorne as both protagonists, Grayson and Jameson, are brought into conflict through their respective fathers. Sheffield Grayson embezzled from his company and seemingly drained his wife’s accounts. Gigi looks for him, and Grayson gets involved to protect Gigi from the truth about their father’s crimes. Ian Johnstone-Jameson solicits Jameson to win a spot in the Game at the Devil’s Mercy, to win back Vantage for Ian.