Louis Creed, the pivotal figure in Pet Sematary's horror narrative, is a man grounded in science. Even as he becomes deeply entangled in a series of irrational horrors, he clings to terms like "experiment" and "diagnosis" to describe his actions. This rational skepticism serves as a symbolic counterbalance to the dark, primal forces of the Micmac Burying Ground. Unlike his literary predecessors, Johann Faustus and Victor Frankenstein, or the stereotypical "mad scientist" of low-budget films, Louis Creed lacks their arrogance and thirst for power. Instead, his tragic flaw mirrors that of Shakespeare's Othello: he "loved not wisely, but too well." King's exploration of love as a catalyst for unspeakable horror is a recurring theme, and it is central to understanding both Louis Creed and the novel itself.

The novel is rich with secondary characters who are crucial to the plot and captivating in their own right. King's talent for creating memorable children is evident in his depiction of Ellie and Gage Creed. Irwin Goldman, Louis's stubborn father-in-law, stands out as one of the most well-conceived minor characters in King's body of work. However, the most intriguing character is Jud Crandall, Louis Creed's eighty-year-old neighbor. Jud serves multiple complex roles in the narrative, acting both as a confidant and a foil to Louis.