Showtime's "Dexter" will find a touch of piety in Season 6, according to The Hollywood Reporter.

In fact, a recently released promotional poster -- shown at right -- foreshadows this new focus.

"The underlying theme of this season is based on religion; it’s based on fanaticism," David Zayas said, who plays Angel Batista. "Season 6 will probably be the darkest season of the six."

Batista will confront professional and personal trials this year, including how religion impacts his life. He's not alone, however. Many of Miami Metro's homicide detectives will explore religious questions.

“He probably, when asked, will give his insight into religion, but Angel has his own challenges with religion that will probably be shown this season,” he said.

Spearheading much of the show's new story arc is actor Edward James Olmos ("Battlestar Galactica"), who stars as a gifted and charming professor of religious studies.

But could Olmos actually be the next villain to attract Dexter's wrath?

“I think every season it’s Dexter [Michael C. Hall] who’s the big bad,” Olmos said. “He’s the one who keeps killing everybody!”

The series follows a serial killer who holds a job as a Miami police forensics specialist while quenching his thirst for the kill by hunting criminals who he believes have escaped justice.

Olmos is part of several new cast additions, including Billy Brown (“Death Row,” "Southland"), Brea Grant ("Heroes," "Halloween II"), Colin Hanks ("The Good Guys") and rapper Mos.

Season 6 premieres Oct. 2 at 9 p.m. ET.

"Dexter" also stars Jennifer Carpenter, James Remar, Desmond Harrington, C.S. Lee, Lauren Vélez, James Remar.