Robert Knepper has become a regular on the NBC's sci-fi drama series Heroes, according to Yahoo! News.

Knepper's character, Samuel, is at the center of the major new story line in which he portrays the charismatic but evil Earth-moving ringleader of a traveling carnival who recruits people with special powers for a mysterious purpose.

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Knepper originally signed for six episodes and so far has appeared in every episode of the show's upcoming fourth season. He follows in the footsteps of another villain on the show, Zachary Quinto (Sylar), who also started off as a recurring character before becoming one of the show's stars.