The world is divided into two main regions: the Ground, inhabited by humans known as Groundlings, and the Sphere, a floating island suspended above the Earth inhabited by Sphereites. Both are separated by the Frontier. Sphereites live in relative comfort compared to those on the Ground. Over time, the Sphere has polluted the Earth by constantly dumping trash, leading to severe environmental risks and a sharp contrast in living conditions.
THE GROUND Main article: The Ground Due to the massive amount of trash dumped from the Sphere, many areas on the ground are toxic. Habitable zones consist of safe zones built in areas outside the Sphere's predetermined debris path.
• Safe Zone Areas where humans can breathe without masks. Various towns are formed here, usually protected by large walls. Cleaners have established their bases and headquarters here. Shops and hospitals function at full capacity, and settlements appear to have large populations. These zones are safe when the sky moves and deadly trash falls. A predetermined route allows Groundlings to build without worrying about falling debris.
• Contaminated Zone The most dangerous area near the settlements. Trash Beasts form here, and humans cannot survive for even 15 minutes without a mask. Large amounts of trash can be found, along with scavengers collecting materials and corpses—especially Sphereite remains—to sell.
• Animals and Plants Main article: Animal and Plant Species Horses have mutated due to the toxic environment into 'Ground Horses.' Dealers prefer them for their robustness; Kuro once used them to pull a cart. Wolves are now extinct. White and black crows, insects, and cats still exist.
Main article: No Man's Land The most dangerous are the 'No Man's Lands.' Cleaners have identified six locations; the average person who enters will die almost instantly. The Trash Beasts in these areas are tougher and dangerous even to Givers.
Both the Ground and the Sphere use an unnamed language. It is used in all Ground writing, such as signs and billboards, and has its own alphabet. There is also a variant similar to Katakana or Hiragana, often seen on the back of Cleaners' uniforms, just below the emblem.
Main article: Hell's Guard The Ground's government is currently unknown, but the primary authority is the Hell's Guard, focused on suppressing criminal activity, especially Givers who abuse their abilities to commit crimes.
Agriculture is extremely difficult due to soil contamination, and flowers are especially scarce. The only exception is the Tori No Man’s Land, which has become a jungle of plants adapted to the toxic environment.
Religion Groundlings lack knowledge or understanding of divine beings. When Mymo mentioned the concept of God, neither the Cleaners nor Countess Knock seemed to recognize the word, let alone its meaning.
Among the Groundlings, some worship the trash dumped from the Sphere, calling it 'Heaven's Blessing.' Whether rotten food or discarded items that pierce their bones or crush their flesh, they call it a blessing, pay homage to it, and force others to do the same.
(This world is a work in progress; some events or characters may change over time.)