As it attempts to recover from a critically-lambasted, ratings-challenged third season, Heroes is casting a variety of roles for its next volume.

The most promising belongs to Robert Knepper, who has already signed on as the show's chief season four nemesis.

Now, Entertainment Weekly's Michael Ausiello has confirmed two more majo casting notes.

First, British actor Ray Park - best known as Darth Maul in Star Wars: Episode I: The Phantom Menace - will play an unspecified character.

Moreover, Deanne Bray will take on an interesting role: a deaf love interest for one of the main Heroes.

Both these actors join Knepper and Madeline Zima (as Claire's college roommate) as recent additions to the cast.

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.