OKAY
This shit got me thinking because this is how I was originally gonna answer your ask, @symonynii
Although Athensphere looks actually really pretty (especially before the Athenspherian Civil War and once the Summoners (besides Tridanen himself (who visits mid-war in the Raid Battle storyline)) manage to visit), Tridanen sculpted Athensphere so that the general look of Athensphere is different to different species. For humans, Athensphere looks like an Elgaia that has really good technology (very much taken over by nature post-war). Green grass, green leaves, flowers of all sorts, blue water and sky. The sun never seems to set on Athensphere, though, instead seeming to dim depending on how tired the individual person is (an effect of the atmosphere, as it is different from Elgaia’s). For demons, however, the greens are now blues, the blues are now varying shades of monochrome, and instead of ONE never-setting sun, there are TWO never-setting suns. However, they are extremely dim for suns, and only count as dim light (especially post-war. I like to think that the view was just so different from what Karl was used to when he came to Athensphere that he actually had to take a minute to process what he was looking at). For gods that aren’t Tridanen (normally referred to by Tridanen as “conventional gods” as Tridanen isn’t exactly considered a god), everything’s a pastel nightmare that would give even a blind god a headache. This was so the conventional gods would mess with Athensphere as little as possible. Tilith didn’t really like Athensphere a lot for this reason, until Tridanen did what he fondly referred to as “changing her lenses”, aka letting Tilith see what he could see. There were a lot of arguments between the group when they officially go back to explore (Karl, Seria, Tridanen, Reda, Lugina, Bertz and Tilith) because the humans though Karl and Tilith were on drugs (basically.). Tridanen sat the fuck by and watched this shit happen without saying what he did, the fucking gremlin.
For Athenspherians (and Tridanen) themselves, though?
Athenspherians see blood red grass and leaves, and golden oceans that seems to shimmer like gold itself (though it is water).
And as for the sky?
There is no sun. Athensphere should’ve never needed a sun, because the technology they had lit up the world. To Athenspherians, Athensphere has grown dark.