Cleon, commonly referred to by the metonym Empire, is the name of multiple fictional characters in the 2021 Apple TV+ television series Foundation. They are the Genetic Dynasty of clones who rule the Galactic Empire. In the series, the 12,000-year-old Empire has been ruled for 400 years by a revolving trio of Cleon I clones: Brother Day, a Cleon in his prime; Brother Dusk, a retired and aging Cleon who serves in an advisory role; and Brother Dawn, a young Cleon being trained to succeed Brother Day. The series is an adaptation of the Foundation series of novels by Isaac Asimov, and stars Lee Pace as Day, Terrence Mann as Dusk, and Cassian Bilton as Dawn. Cloning does not factor in Asimov's novels, though emperors named Cleon I and Cleon II appear as supporting characters.

The trio of Cleon clones are portrayed by Lee Pace (Brother Day), Terrence Mann (Brother Dusk) and Cassian Bilton (Brother Dawn) in the 2021 Apple TV+ television series Foundation. Pace was cast in October 2019, and Mann and Bilton were cast in December 2019. Cooper Carter plays Brother Dawn as a child in season one.

Nick Allen of RogerEbert.com described Pace's performance as "magnetic", and Chancellor Agard of Entertainment Weekly called it a "campy and playful turn". Sean O'Neal of Texas Monthly called Pace's performance "bombastic", and wrote, "Pace was simply born to play a tyrant. His Brother Day comes off like a cross between the Roman emperor Commodus and the Marquis de Sade, a narcissist with swept-back Bradley Cooper hair and a wicked smile that perpetually curls his lips. Pace imbues every line with aristocratic menace, all delivered in his stentorian, Shakespeare in the Park projection." James Dyer of Empire: "Pace brings both weight and humanity to the waning imperium ... while placing a consistent face on the empire at the story's heart." Richard Edwards of Space.com wrote that Pace's performance has "too many echoes of his stern turns" in Guardians of the Galaxy and the Hobbit films. Early trailers for the series prompted online fans to refer to Pace as "Intergalactic Emperor Daddy". Chase Hutchinson of Collider wrote:

Pace continues to give one of his best performances to date. He captures the petulance of the character which is made all the more frightening when considering how he can utterly destroy almost anything that he wants. His terrifying monologue from the end of Season 1 looms large over this as we know he has nearly unlimited resources to carry out vengeance on any who cross him ... There is a humor that Pace brings to the character, showing Day's insecurities when he is challenged with an almost pouty face that is just delightful. He is the type of villain that is worth building an entire show around, making his creation for this story a worthwhile one. His ignorance of so much that is happening around him makes him feel more dangerous as there is always the potential that he could lash out without warning.

Daniel Fienberg of The Hollywood Reporter wrote that "The interplay between Mann and Pace as imperious rulers has strong theatrical energy." Caroline Framke of Variety wrote that at times, "Pace and Mann tap into a shared, visceral disdain that betrays more personality than their respective Cleons would likely care to admit exists." Sean T. Collins of Decider described Mann's performance in "The Last Empress", in which Dusk experiences one shocking revelation after another, as "fascinating to watch", and wrote, "Mann's command of the diverse emotions and affects called for here, making them seem like the product of a single unquiet mind, is deeply impressive." Collins also described Bilton's Dawn as "seemingly aroused equally by the gorgeous Sareth's unabashed come-ons and their secret rebellion against his older bro."

Chaim Gartenberg of The Verge called the Genetic Dynasty "the show's highlight, thanks in no small part to Pace's dynamic performances". Agard explained, "This curious political unit raises interesting questions about individuality and if progress is possible without fundamental change, and it's the main source of fun in the show."

In the 2021 television series adaptation Foundation, the 12,000-year-old Empire has been ruled for 400 years by a revolving triumvirate of Cleon I clones: Brother Day, a Cleon in his prime; Brother Dusk, a retired and aging Cleon who serves in an advisory role; and Brother Dawn, a young Cleon being trained to succeed Brother Day. Though cloning does not factor in Asimov's novels, the television series introduces a "Genetic Dynasty", surreptitiously administered for centuries by the regal Lady Demerzel, secretly a unique, ageless humanoid robot. The clones serve as "the personification of the Empire's permanency, constant and unchanging, ever-present and never-failing." In the story, the Imperial triad scoff at mathematician Hari Seldon's predictions of the Empire's imminent fall, and exile him from the capital world, Trantor, to the distant planet Terminus. But thanks to a devastating and unprecedented terrorist attack, their eyes are now opened to the signs that the Empire is indeed decaying.

In season one, Dawn conceals his color blindness, an anomaly among the Cleons, from Day and Dusk. He and Day also exhibit signs of unprecedented emotions, making them less detached and cruel than their predecessors, which Dusk believes will spell their doom. It is eventually revealed that the rebel movement has tampered with the Cleon genetics, facing the current Day with the fact that the bloodline is now tainted and he, his successors, and likely a number of his predecessors have irrevocably diverged from the original Cleon. Dusk insists that Dawn, who was easily manipulated by the rebels, be destroyed, but Day shows compassion. Demerzel, however, recognizes the danger that Dawn now poses to the dynasty, and kills him.