As production on the series continued, many new and mysterious characters, played by unfamiliar actors and actresses were introduced, but two early cast changes brought stage actors David Ford and Thayer David into the ensemble. Thayer David would go on to play several formidable villains over the course of the series. Michael Currie, as Constable Jonas Carter, was shortly replaced by veteran actor Dana Elcar, as Sheriff George Patterson. Most of the actors played multiple characters, and those characters often returned through flashbacks, the use of parallel time lines, or as ghosts.