World

World, also known as Human World or Earth is where humans reside.

Overview
The world is originally home to humans, devils which have been killed in Hell, fiends which are human corpses possessed by devils and hybrids which are humans with the ability to take the form of a devil. The most prominent area of the world is the country of Japan, where the series takes place.

Japan
Japan is one the countries in the world and the main setting of the series. Its official language is Japanese. It is governed by their Prime Minister who had a contract with Makima. In exchange for working for Japan, any fatal damage inflicted to Makima is redirected to any random citizen of Japan. Public Safety Devil Hunters work for the government of Japan. The higher-ups of the Public Safety Devil Hunters are headquartered in Kyoto, who are also in charge of Makima and her divisions.

On November 10, 1983, the Gun Devil hit Japan for 26 seconds, killing 57,912 people. Aki Hayakawa witnessed the Gun Devil destroying his house and killing his family as it passed by.

On September 12, 1997 the Gun Devil appeared again at the coast of Kaho City in Akita Prefecture for 12 seconds, killing at least hundreds of men, women, and children. However, they are later defeated by Makima and then they possessed the corpse of Aki, turning him into the Gun Fiend. Both Aki and the Gun Fiend are soon killed by Denji. After the defeat of the Gun Devil, Public Safety formed the Anti-Makima Squad with the mission to incapacitate Makima. However, they ended up failing. Later, Denji managed to kill Makima by poisoning her blood and eating her piece by piece which allowed him to bypass the contract between her and the Prime Minister of Japan.

After the defeat of the Gun Devil and Makima, Chainsaw Man became a popular hero nationwide who fights devils. However, his identity is incognito and remains unknown to the general public. This began to change however, due to outside interference keeping Denji from being Chainsaw Man. Following his absence, another Devil Hunter Asa Mitaka took the national spotlight. Her quick rise to fame, impressive feats and general mystery surrounding her caused many conspiracy theories to develop among the public, one of which being that all of Chainsaw Mans past achivements were actually stolen valor from Mitaka instead.

Sometime during March, 199X the Falling Devil hit Japan for an unknown duration of time killing at least 2,000 people.

Sometime prior to 1997 according to Nobana Higashiyama, Japan had seen its adult population's mental faculties decrease because of an American Ultraviolet Ray Weapon sent in Japan's air.

United States of America
The United States of America, shortly known as America (アメリカ) is one of the countries in the world. Its official language is English. It is governed by their President who had a contract with the Gun Devil.

On November 10, 1983, a large terrorist attack involving guns occurred in America, causing that to be the day the Gun Devil first appeared. The Gun Devil hit America for 124 seconds, killing 548,012 people. Aldo, Joey and their brother survived the Gun Devil's attack but lost their home along with their father, mother and grandmother which led them to believe that they are immortal. After the defeat of the Gun Devil, America obtained twenty percent of its body.

On September 12, 1997 the President of the United States applied their contract with the Gun Devil (twenty percent) to attack Makima by sacrificing one year from each citizen of the country because other countries already gave up fighting her. However, this resulted in the defeat of the Gun Devil that America possessed.

Sometime prior to 1997 according to Nobana Higashiyama, the United States was alleged to carry out a large scale operation using ultraviolet rays against Japan which diminished the mental faculties of the adult population (whilst leaving the minors' mental faculties intact).

Soviet Union
The Soviet Union (ソビエト連邦), also known as USSR, is one of the countries in the world, ruled by their Secretary of State. Its official language is Russian.

On November 10, 1983, the Gun Devil hit the Soviet Union for 210 seconds, killing 155,302 people. Later, The Soviet Union confirmed that the Gun Devil had been defeated by someone else and obtained twenty-eight percent of its body.

At some point in time, the Soviet Union kidnapped many children and placed them in a special government program to make super-soldiers dedicated to the country. In this program children were subjected to harsh military training and scientific experiments in order to amplify their natural abilities. A portion of the Bomb Devil's body was placed inside one of the children, thus turning them into a devil-human hybrid. Word of the occurrence was spread throughout the world by an American journalist.

China
China is one of the countries in the world, governed by their General. Its official language is Mandarin and Cantonese.

On November 10, 1983, the Gun Devil hit China for 32 seconds, killing 316,932 people. After the defeat of the Gun Devil, China obtained eleven percent of its body.

Quanxi, who is a hybrid and is known as the First Devil Hunter, and her harem of fiends are from China and work for the General.

After Makima was defeated by Denji, the Control Devil later reincarnated in China as Nayuta, which she was later taken by Kishibe and brought to Japan to live in the care of Denji.

Germany
Germany (ドイツ) is one of the countries in the world. Its official language is German. Its governmental constitution details are unknown or even if it is unified, however a government agent has been seen to hire a devil hunter. At some point in time, the Nazi movement controlled Germany which led to World War II and the Holocaust. However, these all have ceased to exist because of Chainsaw Man's ability to erase things from existence upon consuming them.

One of the perfect dolls of Santa Claus resides in Munich as a famed devil hunter with the alias "Santa Claus of Germany", which is hired by Germany to kill Makima. According to Makima, Germany holds several Devils under their arsenal.

Other Mentioned Countries

 * Canada - On November 10, 1983, the Gun Devil hit there for 7 seconds, killing 8,481 people.
 * India - On November 10, 1983, the Gun Devil hit there for 15 seconds, killing 29,950 people.
 * Mexico - On November 10, 1983, the Gun Devil hit there for 2 seconds, killing 6,088 people.
 * Hawaii - On November 10, 1983, the Gun Devil hit there for 0.4 seconds, killing 780 people.
 * Other countries besides the United States of America, the Soviet Union, and China have four percent of the Gun Devil's body. However, these countries and their percent of body ownership is not mentioned.
 * Other countries besides Japan experienced mass casualties from the Falling Devil's attack. However, these countries and their respective death tolls are not mentioned.
 * Following the worldwide damage caused by the Falling Devil, many nations became impoverished, rising tensions between them and increasing the fear of War.

Trivia

 * In the panel where a street from USA is seen, there is a billboard of Agni who is the titular protagonist of the Fire Punch manga that is also created by Tatsuki Fujimoto.
 * In the world of Chainsaw Man, the following never happened or ceased to exist: Nazis, World War II, the dissolution of the Soviet Union, AIDS and nuclear weapons.
 * In the real world, the USSR collapsed in 1991, but in Chainsaw Man it still exists in 1997. This may be a result of the changes the Chainsaw Devil (or rather devils in general) have made to history.
 * It is implied that Hawaii may be a nation of its own, rather than being part of the U.S.A.
 * In the world of Chainsaw Man, the following existed or happened but now are not remembered by the public consciousness and have been erased from existence (due to the Chainsaw Devil consuming their concept-devil): the Mount Hio eruption, the Holocaust, Nazism, World War II, AIDS, Nuclear Weapons, Arnolone syndrome, Soa, the sixth sense, the light of a particular star that would break children's minds, four other possible conclusions other than death at the end of a living being's life span, and the name of human/devil hybrids.
 * In Japanese, Soa was written as 租唖. 租 roughly means "tax". 唖 means "mute" or "deaf". The meaning behind this is unclear, but it may imply a disease or a condition forcibly causing mutism or deafness under a certain tax.