If I leave the Hidden Library's deeper section through the entrance, everywhere else is dark too, until I get to the world map.
I thought it was the Hidden Library! Brill saying the notes inside Daltah Mines's library were similar, was a good hint!
Nice worldbuilding! More mentions of the Eldolons, whatever they are. Gonna go see if the Earth Crystal will tell me more. Nope. Ah well.