I think this comes in part from the Alessian Order, which equates Daedra with demons, and in part from the need for the writers to have some idiomatic equivalents in Tamriel for stock phrases in English. “To Oblivion with you!” and similar quotes are made by characters all throughout the books we find. The way that Mehrunes Dagon’s plane of the Deadlands is certainly presented that way in The Elder Scrolls IV: Oblivion. Oblivion also gets used in Tamriel as something equivalent to hell. In fact, the phrase “waters of Oblivion” is used heavily in what sources we have, suggesting this metaphor isn’t a million miles off. Maybe a volcanic archipelago is the best analogy for it? That Oblivion itself is a sea, and that the various Daedric realms within it emerge and coalesce as if volcanic matter could be shaped and constructed by the bigger fish out there, who then cocoon themselves in those islands? That really feels like stretching a metaphor, but it’s the best way that I can express having those two ideas coexist at once. It’s described as both a sea, and a myriad of different realms. It’s paradoxical it is a place that is not a place it’s both somewhere that people can go from Mundus, appears to surround it, and possibly overlaps with it.
The first thing to know about Oblivion in the Elder Scrolls is that there is no set definition of it. Subscribe: Anchor | Apple Podcasts | CastBox | Spotify Oblivion and Place