Lumen Pierce was a big part of Season 5 of Dexter, which followed up on the character’s life after his wife Rita was murdered by the Trinity Killer.
Pierce started out as a potential witness that Dexter needed to eliminate, but the two formed a bond when he realized she too had a “Dark Passenger.”
The role earned Stiles an Emmy nomination for Outstanding Guest Actress in a Drama Series, but despite that, there’s been no indication that she’d return.
Eventually, Lumen realized that murder wasn’t something she needed to do anymore, and she bid farewell to Dexter with a promise to keep his dark secret from the world.