The Dexter prequel series Dexter: Original Sin has barely begun, but apparently, it is doing well enough that Showtime thinks a fourth Dexter spinoff is warranted.
Yes, Deadline reports that another prequel is now in development, although interestingly, this will be the first spinoff not to feature Dexter as the lead. In fact, we might not see Dexter in this one at all because it will focus on one of his biggest foes to date: Arthur Mitchell, a.k.a. the Trinity Killer, played by John Lithgow. According to the outlet, this series would focus on how Mitchell became the prolific and terrifying serial killer we know him as, the man who eventually murdered Dexter's wife and Harrison's mother, Rita.
Lithgow has already agreed to return and voice his younger self as Michael C. Hall narrates Dexter's inner monologue in the ongoing prequel series. The actor also previously returned in the Dexter follow-up Dexter: New Blood in a flashback showing what Dexter's son, Harrison, remembered about his mother's gruesome murder.
Along with Original Sin, Dexter has produced a sequel series, New Blood, which aired in 2021, and a follow-up, Dexter: Resurrection, is planned for next year. So, all in all, this long-running Showtime franchise about an avenging serial killer played by Hall (and Patrick Gibson) has spawned quite a significant franchise.
Dexter showrunner Clyde Phillips and another series veteran, Scott Reynolds, will return for the Trinity Killer spinoff as co-creators and executive producers. Deadline reports that this prequel spinoff has been in the works for a while, with scripts already being written as of last spring despite reports wrongly suggesting that the show wasn't moving forward.
Phillips previously said that the entire show was actually already written, though it was "on the back burner" at the time of his comment. The showrunner revealed that Dexter: Resurrection will begin filming in January and air in June 2025, meaning filming for the Trinity Killer show likely won't start until late 2025 at the earliest.
That said, Showtime has not yet ordered this latest spinoff to series, but the future of the Dexter franchise looks promising. Original Sin debuted to a strong start, with over 2.1 million viewers checking in within its first three days on the app. Showtime also reports that the series had the "most-streamed premiere ever."
Dexter: Original Sin is currently airing on Showtime and available to stream via Paramount+ with Showtime.