Foundation Season 3's Incredible Finale Exposes A Massive Cleon Twist That's Been Hidden In Plain Sight For Almost 4 Years
By Dan Bibby
September 12th, 2025
Warning! Spoilers ahead for Foundation season 3's finale, "The Darkness."
Foundation season 3's finale is filled with several twists and turns, and while some are easier to predict than others, certain events were brilliantly misleading. When it comes to the matter of what happened with Terrence Mann's Cleon XXIII, I perhaps feel a little annoyed at myself for not predicting what would happen.
A star of the show since Foundation began back in 2021, Terrence Mann has played multiple versions of Brothers Dusk, Darkness, and also Cleon I. Alongside Cassian Bilton and Lee Pace, Mann has formed an acting trio that's helped bring the Genetic Dynasty to life throughout the space opera's ambitiously vast timeline. In the season 3 finale, Foundation reveals Mann's Cleon XXIII to have the most important role of all his predecessors.
A star of the show since Foundation began back in 2021, Terrence Mann has played multiple versions of Brothers Dusk, Darkness, and also Cleon I. Alongside Cassian Bilton and Lee Pace, Mann has formed an acting trio that's helped bring the Genetic Dynasty to life throughout the space opera's ambitiously vast timeline. In the season 3 finale, Foundation reveals Mann's Cleon XXIII to have the most important role of all his predecessors.
I Can't Believe I Never Made The Connection Between Psychohistory's Purpose & The Clone Emperors' Final Title
From the very beginning of Foundation, the show's primary storyline has revolved around Hari Seldon's (Jared Harris) plan to use his self-developed field of psychohistory in an attempt to shorten the galaxy's "coming darkness." As a blend of history, anthropology, politics, and a number of other fields, psychohistory can essentially predict the future - although that's an oversimplification.
Still, the period of "darkness" that Seldon was referring to was in relation to the fall of the Galactic Empire, led by three clones of Cleon I. While Harris' character states he can't completely circumvent said fall, he claims to be able to shorten the huge amount of time that will pass before another empire can rise in its place. This is why the Foundation was brought into existence - to do just that.
In Foundation season 1, while exploring the lore of the Genetic Dynasty, we learn that the Brothers Day, Dawn, and Dusk actually adopt a fourth title as the clones progress through their lives. They also briefly go by the name Brother Darkness, just before they "ascend" - although Ascension seems very much like a ceremonial execution.
So, the word "darkness" very quickly becomes a pretty loaded term in the lore of Apple TV+'s adaptation of the Isaac Asimov Foundation books. I never made any kind of connection between the two uses of the word, as the concept of a Brother Darkness is never made out to be especially important. As it turns out, there was some intentional misdirection going on.
Hari, probably without even realizing, was predicting the rise of Cleon XXIII, who manages to avoid Ascension in "The Darkness," shortly after adopting the episode's titular moniker. He single-handedly brings Empire to its knees, destroying all the backup clones and even brutally slaughtering the new Brother Dawn. This fulfills Seldon's prophecy, while also making me kick myself for not figuring it all out far sooner.
Still, the period of "darkness" that Seldon was referring to was in relation to the fall of the Galactic Empire, led by three clones of Cleon I. While Harris' character states he can't completely circumvent said fall, he claims to be able to shorten the huge amount of time that will pass before another empire can rise in its place. This is why the Foundation was brought into existence - to do just that.
In Foundation season 1, while exploring the lore of the Genetic Dynasty, we learn that the Brothers Day, Dawn, and Dusk actually adopt a fourth title as the clones progress through their lives. They also briefly go by the name Brother Darkness, just before they "ascend" - although Ascension seems very much like a ceremonial execution.
So, the word "darkness" very quickly becomes a pretty loaded term in the lore of Apple TV+'s adaptation of the Isaac Asimov Foundation books. I never made any kind of connection between the two uses of the word, as the concept of a Brother Darkness is never made out to be especially important. As it turns out, there was some intentional misdirection going on.
Hari, probably without even realizing, was predicting the rise of Cleon XXIII, who manages to avoid Ascension in "The Darkness," shortly after adopting the episode's titular moniker. He single-handedly brings Empire to its knees, destroying all the backup clones and even brutally slaughtering the new Brother Dawn. This fulfills Seldon's prophecy, while also making me kick myself for not figuring it all out far sooner.
The Problem With Cleon XXIII Being The "Darkness" That Seldon Was Talking About In Foundation Season 1
On the surface, psychohistory seems like a cure-all for everything. Being able to functionally predict the future makes it seem strange that the Foundation(s) haven't already overthrown Empire completely. However, even Seldon admits that it's not perfect, and that, by design, it can't account for the actions of individuals. This is why characters like Gaal Dornick (Lou Llobell) and the Mule (Pilou Asbæk) are considered outliers.
Certain individuals can harbor so much power and influence that they can subvert Seldon's predictions, and there's not very much that can be done about it. Generally, psychohistory only works when it comes to huge groups of people. Given the size of the galaxy and how densely populated it is, that's why psychohistory tends to function so well.
So, taking this all into account, it doesn't really make much sense that Seldon predicted Cleon XXIII's arrival and that he would end the Cleonic Dynasty while going by the name of Brother Darkness. Seldon made his calculations centuries before Cleon XXIII would ever exist, so Harris' character wouldn't have been able to fold this particular Brother Darkness into those broad predictions.
To argue briefly against myself, I suppose it is possible that the dual meaning of "darkness" was indeed a coincidence within the Foundation universe. Cleon XXIII grew up knowing about Seldon's calculations and the darkness that was coming for Empire, including the rough date it would all end. If so, maybe he thought it would be fitting to prove Seldon right when the time came for him to change his name. It's a bit of a stretch, but it's all I've got.
Certain individuals can harbor so much power and influence that they can subvert Seldon's predictions, and there's not very much that can be done about it. Generally, psychohistory only works when it comes to huge groups of people. Given the size of the galaxy and how densely populated it is, that's why psychohistory tends to function so well.
So, taking this all into account, it doesn't really make much sense that Seldon predicted Cleon XXIII's arrival and that he would end the Cleonic Dynasty while going by the name of Brother Darkness. Seldon made his calculations centuries before Cleon XXIII would ever exist, so Harris' character wouldn't have been able to fold this particular Brother Darkness into those broad predictions.
To argue briefly against myself, I suppose it is possible that the dual meaning of "darkness" was indeed a coincidence within the Foundation universe. Cleon XXIII grew up knowing about Seldon's calculations and the darkness that was coming for Empire, including the rough date it would all end. If so, maybe he thought it would be fitting to prove Seldon right when the time came for him to change his name. It's a bit of a stretch, but it's all I've got.
Brother Darkness Becoming The Sole Emperor Returns Foundation To Issac Asimov's Cleon Book Canon...Sort Of
Cleon I is a character in the Foundation books, as is Cleon II. The difference is, they're blood-related, but not clones. Plus, they don't have a particularly big part in the story. The Clone Dynasty is original to the Apple TV+ version, and I think it's one of the best creative choices the writers made when bringing Asimov's literary space opera to the small screen.
So, rather than there always being three emperors at once in the Foundation books, there is only ever one at a time. In the show, Cleon I was the sole leader of Empire, but the Dynasty has been in place ever since. In a way, Cleon XXIII, being the only active emperor, brings Foundation back to its roots.
It's a cool tribute to the source material, although it's also incredibly disappointing from a storytelling perspective. With reports that Foundation season 3 had its budget reduced mid-production, Darkness' plot to end the Dynasty further supports my theory that the show is getting rid of stars like Pace and Bilton to save money in the future. I hope I'm wrong, but I'm not hopeful.
So, rather than there always being three emperors at once in the Foundation books, there is only ever one at a time. In the show, Cleon I was the sole leader of Empire, but the Dynasty has been in place ever since. In a way, Cleon XXIII, being the only active emperor, brings Foundation back to its roots.
It's a cool tribute to the source material, although it's also incredibly disappointing from a storytelling perspective. With reports that Foundation season 3 had its budget reduced mid-production, Darkness' plot to end the Dynasty further supports my theory that the show is getting rid of stars like Pace and Bilton to save money in the future. I hope I'm wrong, but I'm not hopeful.
Brother Darkness Ending The Cleonic Dynasty Sets Up A Great Twist Ahead Of Foundation Season 4
As part of his plan to end Empire, Brother Darkness also had to take care of Lady Demerzel (Laura Birn). In a heart-wrenching scene that I won't soon forget, Demerzel's sacrifice fails to save the newly-decantated Cleon XXVI. While it initially seems that the death of the last robot in the galaxy is the end of that particular arc, "The Darkness" throws in one more compelling twist to end Foundation season 3.
Demerzel's remains, which form a two-headed clasp with the robot Brother Day brought back from Mycogen, contribute to getting a message back to...Earth's moon?! Yes, Demerzel was not the last robot, and it doesn't seem like she was anything close to being so.
Although it may not seem like it at times, Foundation is set in a universe where Earth exists and humans originated there centuries earlier. The planet has a vital role to play in the books, so it's great to see Apple TV+ keeping an eye on the source material, despite the big changes that have been made.
Asimov wrote a great many robot books, and while Foundation wasn't always heavy on that lore, the space opera shares a continuity with those stories. This has already been softly confirmed in the show by the mention of the war between robots and humanity, as well as Asimov's laws of robotics. Seeing robots living on Earth's moon in "The Darkness" feels incredibly Asimovian, and I can't wait to see that arc get more attention in the recently confirmed Foundation season 4.
Head to Talk Nerdy To Me's TV page for more coverage of your favorite shows.
Demerzel's remains, which form a two-headed clasp with the robot Brother Day brought back from Mycogen, contribute to getting a message back to...Earth's moon?! Yes, Demerzel was not the last robot, and it doesn't seem like she was anything close to being so.
Although it may not seem like it at times, Foundation is set in a universe where Earth exists and humans originated there centuries earlier. The planet has a vital role to play in the books, so it's great to see Apple TV+ keeping an eye on the source material, despite the big changes that have been made.
Asimov wrote a great many robot books, and while Foundation wasn't always heavy on that lore, the space opera shares a continuity with those stories. This has already been softly confirmed in the show by the mention of the war between robots and humanity, as well as Asimov's laws of robotics. Seeing robots living on Earth's moon in "The Darkness" feels incredibly Asimovian, and I can't wait to see that arc get more attention in the recently confirmed Foundation season 4.
Head to Talk Nerdy To Me's TV page for more coverage of your favorite shows.