Previously Seen: Mostly on British TV, including the role of Marian on BBC's "Robin Hood" and the ITV1 miniseries "Collision."
Expected Breakout Role: As new vamp Nora on season five of HBO's supernatural soap "True Blood," returning June 10.
Why: Nora is bound to stir up trouble for key characters Bill, Eric and Sookie. Since she was sired by Godric she's considered Eric's "sister," and she's also a key member of the Vampire Authority. Fans of Charlaine Harris' "Southern Vampire Mysteries" may already know where Griffiths' character is heading, but suffice it to say she'll play a significant role in a season that promises to be heavy on "vampire politics."

- Geoff Berkshire