Stapleton is motivated by greed and ambition, seeking to eliminate heirs and claim the Baskerville fortune.
Mrs. Stapleton is his sister and accomplice, though she suffers under his manipulation and cruelty.
Stapleton targets Sir Henry as the heir to be eliminated to secure the estate.
Holmes is Stapleton’s intellectual adversary, working to expose and stop him.
He fears exposure and failure to secure the estate.
He desires power, wealth, and to conceal his true identity.
Stapleton lacks a conventional moral compass, acting immorally and without remorse to achieve his goals.