- You may be looking for Coup against Rassilon.
The coup against Urizen (PROSE: The Cactus and the Corpse [+]Aristide Twain, Horrors of Arcbeatle (Auteur, Coloth, Arcbeatle Press, 2023).) was the event which led to Urizen losing his status as uncontested ruler of the Morning Star. According to Olivia Kagg Waldermein, it was "much-mythologised" and was the "bridge" between the founding era of the planet's history and its modern age. (PROSE: Love & War [+]Aristide Twain, adapted from The Diplomat (Aristide Twain), The Book of the Snowstorm (Dionus, Arcbeatle Press, 2023).)
Declaring "God", alias Urizen, "unfit for command", his "angels" deposed him. Because he was immortal, they did not kill but simply "cleaved" his "eternal spirit" from his "undying flesh". The former was then "buried beneath the Cathedral like a dirty secret". There, (PROSE: The Cactus and the Corpse [+]Aristide Twain, Horrors of Arcbeatle (Auteur, Coloth, Arcbeatle Press, 2023).) within the caldera, (PROSE: The Book of the War [+]Lawrence Miles, et al., Faction Paradox novels (Mad Norwegian Press, 2002).) "Urizen's disembodied mind" led the spirits of other dead Elementals - his "angels" - to use "their own mental powers to generate a simulated block-transfer environment within the anomalous void", a "self-sustaining virtual afterlife" corresponding to (PROSE: Love & War [+]Aristide Twain, adapted from The Diplomat (Aristide Twain), The Book of the Snowstorm (Dionus, Arcbeatle Press, 2023).) the virtual reality within the Matrix. (TV: The Deadly Assassin [+]Robert Holmes, Doctor Who season 14 (BBC1, 1976).) Meanwhile, an "anonymous line of figureheads" replaced Urizen as Supreme Beings. (PROSE: The Cactus and the Corpse [+]Aristide Twain, Horrors of Arcbeatle (Auteur, Coloth, Arcbeatle Press, 2023).)