For the Emperors named Cleon, Brother Dawn (Cassian Bilton), Brother Day (Lee Pace), and Brother Dusk (Terrence Mann), it’s all about showing up as a clone of themselves over the centuries. But the episode’s biggest twist is connected to Brother Day’s attempt to flee the palace with his lover, Song (Yootha Wong-Loi-Sing). Brother Day tells Song the secret of his robot master. In Demerzel, Foundation not only honors Isaac Asimov’s later Foundation novels, but also the robot books that connect to his larger literary canon. In this episode, Demerzel says she’s erased Song’s memory of ever meeting Brother Day.