Holmes is a private consulting detective who operates out of London. He possesses astounding deductive abilities and relies strictly on cold logic, physical evidence, and scientific reasoning to solve cases. He takes on the Baskerville mystery with clear skepticism toward the supernatural rumors, viewing the situation as a calculated earthly crime rather than a ghostly curse.

A medical doctor and military veteran, Watson shares the Baker Street flat with Holmes. He documents their cases and frequently travels into the field to gather intelligence when Holmes is occupied in London. He brings a practical, courageous approach to the investigation and serves as Sir Henry's armed bodyguard during their stay at the isolated Baskerville Hall.

Sir Henry is a sturdy, pugnacious man in his thirties who recently arrived from Canada. As the nephew of Sir Charles, he is the last known heir to the Baskerville estate and its vast fortune. Despite the gloomy environment and the threats on his life, he insists on moving into his ancestral home and plans to modernize the property with electricity.

Dr. Mortimer is a tall, thin surgeon with a beak-like nose who practices medicine in the rural area near Dartmoor. He was the personal physician to the late Sir Charles. He brings the case to Holmes out of genuine concern for Sir Henry, though he personally harbors fears that the hound legend might be supernatural.

Stapleton is a slim, clean-shaven naturalist in his thirties who resides at Merripit House on the moor. He spends his days studying local plants and insects, possessing an unusual knowledge of the dangerous Grimpen Mire bogs. He acts as a welcoming, eccentric neighbor to the new residents of the Hall.

Beryl is an elegant, dark-complexioned woman from Costa Rica who lives at Merripit House. She is deeply anxious about the legends surrounding the moor and the danger they pose to the Baskerville heirs. She actively tries to push Sir Henry away for his own safety.

Barrymore is the tall, handsome, and thickly bearded butler of the Baskerville estate. He and his wife are longtime servants who intend to leave their posts once Sir Henry is settled. His solemn demeanor and strange habit of creeping around the empty upper floors at night arouse early suspicion.

Mrs. Barrymore is a large, heavy-featured housekeeper with a stern expression. Despite her stoic public demeanor, she is heard sobbing intensely in the middle of the night, indicating a deep, unshared sorrow. She handles domestic duties while harboring secrets regarding the surrounding moor.

Selden is a notorious convicted murderer who escaped from a nearby prison and survives in the harsh conditions of the moor. Described as feral and brutal, his presence forces the military to guard the train stations and creates tangible physical danger in the area.

Laura is a beautiful woman living in the nearby village of Coombe Tracey. Estranged from a cruel husband, she runs a small typing business heavily subsidized by local benefactors. She arranged a meeting with Sir Charles on the night of his death but claims she never attended.

Inspector Lestrade is a small, wiry, bulldog-like detective from the London police force. He travels to Devonshire to lend official law enforcement authority to Holmes's private investigation.

Cartwright is a young boy who works for a message delivery service in London. Holmes hires him to run errands, search for clues, and gather intelligence quietly. He later travels to the countryside to deliver supplies and messages.

Sir Charles is the recently deceased uncle of Sir Henry. He made a fortune in South Africa before returning to restore his ancestral home and donate to local charities. His failing heart and deep fear of his family's legendary curse culminated in his mysterious death near the moor gate.

Mr. Frankland is an elderly neighbor who enjoys initiating petty lawsuits against the local townsfolk and police. He spends his days scanning the desolate moorland with a telescope, hoping to spot the escaped convict or other trespassers.

Hugo Baskerville is a notorious 17th-century ancestor of the Baskerville line. According to the manuscript, his cruel and drunken behavior during the English Civil War era led him to kidnap a maiden, an act that supposedly brought a demonic curse upon his bloodline.