What is the name of the stepfather in 'The Adventure of the Speckled Band'?

The stepfather in “The Adventure of the Speckled Band” is Dr. Grimesby Roylott. He is the violent and financially troubled head of the Roylott household at Stoke Moran, where Helen Stoner seeks Sherlock Holmes’s help.

Roylott had been a doctor in India and served prison time after killing his Indian butler in a fit of anger. After returning to England, he married Helen and Julia Stoner’s mother. When she died in a railway accident, the sisters remained under Roylott’s control at the heavily indebted family estate.

Roylott’s motive is financial. Under the terms of his wife’s will, each daughter would receive income if she married, reducing the money available to him. He therefore arranged Julia’s murder and attempts to kill Helen using a trained venomous snake sent through a ventilator.

The story’s famous “speckled band” is not a human gang but the snake’s markings. Holmes identifies the creature as a swamp adder, though the species is fictional. The character is sometimes confused with Professor Moriarty, Colonel Moran or Stapleton, but none of those men appears as Helen’s stepfather in this story.