What is the name of the villain in 'The Adventure of the Copper Beeches'?

The villain in “The Adventure of the Copper Beeches” is Jephro Rucastle.

Rucastle hires Violet Hunter as a governess under bizarre conditions: she must cut her hair, wear a particular dress, and sit where she can be seen from outside. Holmes eventually discovers that she resembles Rucastle’s daughter, Alice, whom he has confined to prevent her from marrying and claiming an inheritance.

The case is sometimes confused with other Holmes villains. Professor Moriarty is Holmes’s criminal mastermind nemesis, while Dr Grimesby Roylott is the violent stepfather in “The Adventure of the Speckled Band.” Rucastle is a different kind of antagonist: his scheme depends on coercion, imprisonment, deception, and financial control rather than a famous criminal network.

The story was first published in The Strand Magazine in June 1892 and became the final story in The Adventures of Sherlock Holmes. Its plot also explains the unsettling locked wing and the vicious mastiff Carlo.