The Fallen city of Altair (死滅都市アルテア Shimetsu Toushi Arutea?) was once supposed to be a utopia built for the co-existence of Humans and Habs. Its infrastructure is balanced between the supporting systems on the surface and the float-energy plant that levitates the city.
The city was built with a state-of-the-art Force furnace to synthesize limitless amounts of Creation Force. Instead the furnace malfunctioned, and the reaction produced leaking Destruction Force that left the city in ruins, leaving the remaining inhabitants corrupted into Shade zombies as of present.