Brother Day is one of the main characters of Foundation. He is portrayed by Lee Pace in the upcoming Apple TV+ series. Both intimidating and larger than life, Brother Day is the latest in a long line of clones and the current ruling Cleon, Emperor of the Galaxy. He is capable of being charming but also prone to volcanic eruptions of anger.
Brother Day is the current ruling Emperor of the Galactic Empire. He rules with Brother Dusk and Brother Dawn by his side. As the primary Cleon, protocol states that he should never leave Trantor to ensure his safety.
Brother Day is worried about the predictions made by Hari Seldon as to the fate of the Empire, believing that Hari might be a revolutionary out to destablize the Empire from within. However, Hari is not Day's only problem. The Outer Reach planets of Anacreon and Thespis are involved in a mining dispute over an asteroid that resulted in the deaths of several Imperial appraisers. Day receives delegations from both planets in an effort to maintain the peace.
After the terrorist attack on the Star Bridge, Day decides to exile Hari and his Foundation out to Terminus. If the predictions of Psychohistory falter, then the project will be left to wither. If the predictions are accurate, then Imperial support will ensure that the successes of the Foundation can be used to bolster the Emperor's regime.
Evidence comes to light that the bombers came from both Anacreon and Thespis, forcing Day to interrogate the diplomatic delegations from each planet. Despite their protestations of innocence, and Jerril's belief that their hate each other more than their hate Empire would not lead them to working together, Day decides to punish them. In a public ceremony, Day executes the delegations aside from the primary ambassadors, and orders Imperial ships to bomb both planets.
As Brother Day, Cleon XIII oversaw an Empire beset by turmoil; religious disagreement rising from Luminism, homegrown insurgency on Trantor, and the Outer Reach planets defying the Empire. Day firmly believed the blame for this was the impulsive actions on his predecessor, Cleon XII, who allowed Hari Seldon to enter exile and ordered the bombing of the planets Anacreon and Thespis. In an attempt to steady the Empire, Day resolved to travel to the funeral of Proxima Opal to install a favored successor as her replacement, breaking with protocol that the primary Cleon should never leave Trantor.
From the Foundation Books
While Brother Day is an original creation for the Foundation television series, he does have a counterpart in the Foundation series -- Emperor Cleon I. Last Galactic Emperor of the Entun dynasty, Cleon I ruled from the planet Trantor. Amiable and not enthusiastic about his position as Emperor, Cleon I relied on his Chief of Staff, Eto Demerzel, to conduct the day to day business of running the Empire.
Cleon I was insulated from his own Empire, confined to the grounds of the Imperial Palace on Trantor. He eventually learned of Hari Seldon and his new science of Psychohistory and took an immediate interest. The Emperor used Seldon’s predictions as a tool to prevent unrest within the Empire, eventually installing him as his new Chief of Staff upon Demerzel’s retirement.
- Season One