"The Eye Above the Mantle" by Frank Belknap Long

Published in 1921

Nietzsche, of course, had written about his Übermensch starting in the 1880s, so this was hardly a new idea at the time this story was written. Probably Long had been reading Nietzsche to get the idea for this story?

Arabian goddess Aso: I can't find ANY reference to such a deity in the pre-Islamic Arab world. But I don't speak or read Arabic and so can't make any productive use of Arab google or other Arabic sources. If you know anything about this, please leave a comment below. But I wouldn't be surprised if it ended up being a made-up name with no historical mythological counterpart.

the gods of Seth and Sarmenia: It appears Sarmenia was an actual historical place in the 12th and 13th centuries AD. Perhaps a city? Definitely in the Levant, so part of the Crusader state of the Kingdom of Jerusalem. But I don't see any reference to Sarmenia as a god. But the way the word is used here, and given several references already to things Arab, this being a reference to the local gods of a city of Sarmenia in the Levant would make sense. Seth is an alternate spelling for the Egyptian god Set, and obviously Seth is a Biblical figure as well, being the third son of Adam and Eve, but neither of these is a good fit here. Not sure what it is meant to be about.

Heth: while this is surely meant to refer to some person the narrator knows personally, and not any historical or mythological person, it is interesting that there was a Biblical person named Heth, being the second son of Canaan (son of Ham, son of Noah).

the demon Roth: Perhaps this is meant to be Astaroth? I don't know what Dagaan would be though.

Rosath and Raynald: It seems increasingly likely that most or all of the names used in this story are fictional. These certainly don't appear to have any historical counterparts that I can dig up.

The picture used is "Composite Venera 10 panorama" by zELARiO used here under the Creative Commons Attribution 3.0 Unported license (https://creativecommons.org/licenses/by/3.0/).

Long couldn't have known it in 1921, but a limitless plain under a yellow sky with no hint of the sun sounds an awful lot like the surface of Venus! So that's the picture we're using here. Or anyways an artist's re-rendering of it, helpfully removing any bits of the Venera lander from the view.