Anthony James Marston (Tony Marston), an amoral and irresponsible young man
Thomas Rogers, the butler and Ethel Rogers' domineering husband
Ethel Rogers, the cook/housekeeper and Thomas Rogers' wife
General John Gordon MacArthur, a retired World War I war hero
Emily Caroline Brent, an elderly, pious spinster
Edward George Armstrong, a Harley Street doctor, is an old fashioned self made man, that Sells luxury to old ladies, he works a lot
William Henry Blore, a former police inspector, now a private investigator
Philip Lombard, a soldier of fortune (A person willing to work for or ally himself with any person or institution who will take him on.)
Vera Elizabeth Claythorne, a young woman on leave from her position as a sports mistress at a girls' school
Lawrence John Wargrave (Mr Justice Wargrave), a retired criminal judge
Isaac Morris, the island's owner, a sleazy lawyer and drug trafficker
Fred Narracott is a sailor living in Devon. He makes deliveries to Soldier Island, and transports passengers there. He regularly comes down to the island every morning, to deliver mail and supplies.