'The Mentalist' Season 6 Spoilers: Rockmond Dunbar Promoted to Series Regular

A character who has yet to debut on CBS' "The Mentalist" has already been promoted to series regular. 

Rockmond Dunbar's role has already been upped to a recurring part, TVLine confirms, ahead of his premiere episode. 

The "Sons of Anarchy" alum was initially hired for a three-episode arc. He will play Dennis Abbot, a hardline FBI Supervisory Agent who is unimpressed by Patrick Jane's (Simon Baker) detective skills or smooth-talking charm. His first episode will air on Nov. 10. 

Abbot is one of two new characters added to the show's sixth season to replace the midseason exits of Amanda Righetti and Owain Yeoman. Another replacement character will be FBI agent Kim Fischer ("Monday Morning's" Emily Swallow), an ex-homicide detective who hails from Dallas and has strong convictions. 

Dunbar is joining the darkest "Mentalist" season yet, with a death occurring almost every episode thus far. On the last episode, "Red Listed," Bob Kirkland was shot and killed, further narrowing down the list of Red John suspects. 

The noticeably darker tone of the show was a conscious decision, said series writer Rebecca Cutter. The humorously witty dialogue has been tempered as Jane gets closer to revealing the murderer who killed his wife and child. 

"I really enjoy writing the humor; I love writing Jane's dialogue," Cutter told The Inquisitr. "This whole season has been a little gorier than normal. There are other shows out there where cutting off fingers is no big deal; that's like nothing. But on our show, that's darker than we usually go."

The clues that fans learned in this past episode will come to light later on in the season.

"That all will come to bear a lot, coming down into the final episode, when we reveal who Red John is," Cutter said. "All of that will blow up and be explored very thoroughly and have bigger implications for CBI."

In the next episode, "Red Tattoo," Red John suspect Ray Haffner will return to assist on a case.

The synopsis reads, "When a prominent member of Visualize is mysteriously killed, Jane investigates in the hopes that the case will provide a clue that will lead him to Red John."

"Red Tattoo" airs Sunday, Oct. 27 at 10 p.m. on CBS.