John Lithgow Added To The Dexter Revival Cast: Here's What It Could Mean

The limited series revival of Showtime's "Dexter" returns in the fall, and everyone is excited to find out what's happening with their favorite serial killer. There are plenty of questions that need answering, like: How did Dexter end up in Iron Lake, New York? Has he continued seeking out vile criminals to feed his killing addiction, or is he on the path to redemption? And who is that wrapped in cellophane in the teaser?

There's still so much we don't know about the new series, although a few details have come to light — like who will be joining the show's star, Michael C. Hall, as he returns down the path of murderous mayhem. Clancy Brown will play Kurt Caldwell, Iron Lake's local big rig business owner with a dark secret, and the show's main villain (via Deadline). However, Deadline also just announced a returning actor in the new series, John Lithgow, who played the menacing Trinity Killer in "Dexter" Season 4.

As arguably one of Dexter's biggest adversaries, it's no surprise that Showtime would want to bring the Emmy-winning Lithgow back into the fold. However, as fans remember, Lithgow's character was killed by Dexter in the show's Season 4 finale, so what role could the Trinity Killer possibly play in Dexter's new life?

Although John Lithgow's chilling performance in "Dexter" Season 4 was one to remember, here's a quick recap for those who may have forgotten. While trying to juggle a family and a new baby, Dexter is having a tough time fitting his side hobby into his busy schedule. That's when he meets Arthur Mitchell, aka the Trinity Killer, and is shocked to discover that unlike himself, Arthur is able to balance his seemingly perfect family life with his own serial killer tendencies. Hoping to learn from him, Dexter integrates himself into Arthur's circle, but to his own detriment. Although Dexter succeeds in putting down the Trinity Killer, he is unable to prevent the tragic murder of his wife, Rita (Julie Benz), who is killed by Arthur.

So how will Lithgow's Trinity Killer appear in the new episodes of "Dexter?" Fans will remember that Dexter frequently references what he calls his Dark Passenger — the part of him that has a hunger to kill. The Dark Passenger has often manifested as Dexter's father, Harry (James Remar), who taught Dexter at a young age how to kill without getting caught, using a set of rules known as the Code. Yet as Dexter discovers in Season 8, it wasn't Harry Morgan who invented the Code, but Dr. Evelyn Vogel (Charlotte Rampling). As a result, Dexter realizes that he no longer needs "Harry," and the subconscious figure disappeared.

While we don't know for certain, perhaps Dexter's Dark Passenger will return, this time with the Trinity Killer's face. If so, will he be a force for good, like Harry was, or will he drive Dexter to his inevitable doom? We'll find out when "Dexter" returns to Showtime in fall 2021.