A central figure whose mysterious death drives the investigation. Known only through memories and insights gleaned by Cordelia, his character unfolds as a central enigma within the story.

A former police officer who co-founded the detective agency with Cordelia and promoted her before his untimely death. Although not present in the novel, his influence on Cordelia is significant.

A prominent microbiologist and father figure with complex motivations, whose actions and relationships are pivotal to the novel's mystery. His character embodies themes of deception and duality.

A multifaceted character who serves as both Sir Ronald's secretary and a parental figure, interwoven in the fabric of deception surrounding the central mystery. Her role intensifies the novel's exploration of complex relationships.

A chief superintendent whose indirect presence reinforces the novel's authority while showcasing Cordelia's abilities. His dynamic with Cordelia adds layers to the detective genre's representation of moral dilemmas.

An assistant to Sir Ronald whose actions complicate the investigation. His character highlights the contrasting relationships and loyalties within the narrative.