Charon Prime - Artificial World

Inner Surface.

Yesterday I told you about reasons why Unnamed World is unnamed. Today I want to reveal something more. As I'm writing this post in the middle of the night, it will have rather loose, modular form.

• As I mentioned before, humans are rather young race on Charon Prime. Its original rulers, now called the Hollow Ones, disappeared without a trace long before the first humans landed on the planet (about eight thousand years before it) and ruled for maybe 100000 years.
• Hollow Ones weren't the first visitors of Charon Prime. In fact, there was no Charon Prime before their arrival. Hollow Ones created the Charon Prime.
• Charon Prime fits into the Hollow Earth model, but there is no sun inside it - there is only darkness. Inner layer of the world seems to be dead and abandoned but who knows what nightmares lurk there...
• Almost no one knows about the "inner world".
• Some of the ancient machinery of the Hollow Ones are still active, buried deep inside the planet. At least one of them is used by humans (power core of the City of Rust) but it's almost certain that no one knows a shit about the origin and nature of this machinery.
• Several megadungeons (or even something like gigadungeon) may be placed between the outer and inner surfaces of the planet. It's highly possible that they are really dangerous places.
• Even the outer surface of the Charon Prime is not very similar to our Earth. It's barren and dead, landscapes have surreal shapes and it's dotted by immense ruins of strange buildings of unknown purpose. Inner surface is even more alien and hard to describe. Generally, some regions of the "regular surface" were inspired by landscapes by Zdzisław Beksiński (especially from 80s), while the inner one was greatly inspired by bio-mechanical landscapes of H.R. Giger. Kinda obvious, eh?