Yeah, it sorta makes Void Century not only about the dark history of the celestial dragon, and add in the sunken world history into the mix. Maybe that’s why Mary Geoise is located on top of Red Line, the highest point of the world, and maybe them forbidding the study of Void Century is because they wouldn’t want people to locate to the Red Line due to their sunken island. I’m sure whatever Enel does and the moon will get pull into the story as well.