Vera is a young former games mistress working at a third-class school who accepts a secretarial job for the mysterious Mrs. Owen. She is practical and observant but harbors deep anxiety, frequently experiencing sensory flashes related to water and her past role as a governess. She attempts to maintain a cool, professional exterior while quietly evaluating the strange circumstances and the other guests around her.

A recently retired judge, Wargrave possesses a formidable reputation in the legal profession and commands a room with his calm, authoritative demeanor. He quickly assumes a leadership position when panic erupts among the guests during their first evening. He relies heavily on logic and facts, treating the strange events on the island like a court case that needs to be systematically dismantled.

A resourceful, athletic man with a mysterious background involving military service in East Africa. He travels to the island after an intermediary offers him a sum of money to handle unspecified tasks for the owner. He approaches danger with a calm, almost amused confidence, openly carrying a revolver and maintaining a sharp watch over his fellow guests.

A former police officer turned private investigator who initially presents himself to the group under the alias "Davis." He brings a practical, law-enforcement mindset to the island and frequently monitors his fellow guests for suspicious behavior. He is physically imposing and methodical, though his lack of imagination sometimes limits his investigative approach.

A prominent, affluent London physician who travels to the island ostensibly to treat the host's nerves. He strives to maintain his respectable professional facade while privately struggling with the memory of a past medical error committed under the influence of alcohol. He frequently defers to recognized authority figures and relies on scientific logic to dismiss irrational fears.

A strict, 65-year-old woman with severe religious principles and a harsh view of modern morality. She accepts her invitation assuming it comes from a former guest house acquaintance. She judges her fellow guests harshly, refusing to discuss the accusations made against her and attributing any misfortune to divine retribution for sinful behavior.

An elderly, retired military veteran who arrives on the island expecting to reunite with old acquaintances. He lives a withdrawn, lonely life, convinced that others whisper about a tragedy involving an officer from his unit nearly thirty years ago. He is weary and highly sensitive to social judgment, feeling increasingly resigned to his situation as the tension rises.

A tall, gray-haired, and highly respectable butler hired alongside his wife to prepare the mansion for the arriving party. He executes his duties with professional efficiency despite having never met his employer face-to-face. He pays close attention to the household details, becoming the first to notice anomalies like the disappearing soldier figurines on the dining room table.

The mansion's cook and maid, presenting as a pale, monotonous woman who appears constantly frightened of her own shadow. She operates in a state of high anxiety and relies heavily on her husband's direction while performing her household duties. The strange environment and unexpected accusations quickly take a severe physical toll on her nerves.

A wealthy, handsome, and carefree young man who drives recklessly and lives for excitement. He views the invitation to the island as an opportunity for drinking and socializing with high society. He lacks a sense of moral responsibility, casually dismissing past mistakes and tragedies as minor inconveniences that simply interrupted his life.

A local sailor from Sticklehaven tasked with transporting the guests and supplies to Soldier Island. He observes the arriving party with quiet judgment, noting that they lack the wealth and glamour he expected from the mysterious new island owner.

A shadowy figure who acts on behalf of the unknown island owner to hire specific guests and make logistical arrangements with the locals of Sticklehaven. He operates behind the scenes to ensure the guests arrive on schedule.