Obscure era of The Elder Scrolls lore: conquest of the heavens undertook by the Second Empire of Man (i.e. Reman Empire).
Greatest emperor in history of mankind, Reman Cyrodiil, Worldly God, born of divine hierogamy of Alessia, Nirn itself, and Hrol, king form Beyond-the-Twilight, after failed attempt to conquer the underworld looks to the skies and desires to expand human dominance to spaces among the stars. He breaches the Liminal Boundaries by sheer force, he REACHES HEAVEN BY VIOLENCE. Great fleets of mothships crewed be Imperial Mananauts explore the dark beyond Nirn, discover mysteries of the Aedric worlds, infinite spaces only because of mortal stress perceived as spheric objects i.e. planets. Strange landscapes of the bodies of dead-dreaming gods, populated by beings stranger than any Daedric demon you can encounter. Discovering lost colonies of men established during ritual exploration of the outer heavens undertook during empress Hestra the Red, during the First Empire, peoples long lost to the alien worlds, transformed by Aedric magic. Bargaining with Daedra, crafting future and glory for mankind in unclaimed, pure creatia of unclaimed Oblivion in between the stars. Conflicts with Altmeri sunbirds which are pure Aetherial sunlight and Dunmeri vehkships powered by belief-engines.
A glorious game that’ll never be made.