Hester Harper
Hester Harper or Miss Harper is the main character. She grows an unhealthy obsession with the young Katherine whom she takes under her wing and wants to keep her out of the outside world.
Katherine
Katherine is the orphan girl whom Miss Harper takes under her care. Katherine is naive and innocent, but also very adaptable.
Mr. Bird
Mr. Bird is Miss Harper's father's old friend. After her father's death it is him who takes care of the dear Miss Harper who completely changes and starts behaving recklessly blinded by her obsession with Katherine.
Mrs. Borden
Mrs. Borden is the wife of the property owner. She is also a sort of Miss Harper's rival in the sense that the two women chose completely different paths in life.
Joanna
Even though Joanna is not an active character her presence in the plot is strong. She awakens jealousy in Miss Harper and represents an inevitable threat.