Who is the main antagonist in 'The Hound of the Baskervilles'?

The main antagonist in 'The Hound of the Baskervilles' is Jack Stapleton. He appears to be a mild naturalist living near Baskerville Hall, but Sherlock Holmes eventually exposes him as the murderer behind the mystery.

Stapleton is secretly Rodger Baskerville II, a distant relative who wants to eliminate the remaining heirs and claim the family fortune. He exploits the old legend of a supernatural hound by keeping a fierce dog, training it to follow the Baskervilles' scent, and coating its face with phosphorus to create a terrifying appearance.

Stapleton first helps create suspicion around the supposed curse by behaving like an interested neighbour while secretly plotting against Sir Charles and Sir Henry Baskerville. His wife, Beryl, is presented as his sister, another deception that helps conceal his crimes.

Readers sometimes mistake the hound itself for the antagonist, but it is only Stapleton's weapon. Selden is an escaped convict and a red herring, while Dr. Mortimer and Sir Henry are allies or victims. Stapleton disappears into the Grimpen Mire during the final pursuit.