Amanto is the Japanese blanket name for the outer space aliens in the universe of Gintama. They and the organizations they formed have directly or indirectly influenced every character's lives in the series.
Background[]
Like what will later happen to the Earthlings, the Amanto had their lives changed when they discovered a revolutionary new power source called Altana, a planetary life force. When they found a way to convert it to energy, it could now be used to advance faster than light travel and upgrade the power of weaponry. This sparked a series of devastating wars over this valuable resource. Years later, the surviving planets decided to create an organization independent of their control to monitor Altana usage lead by a small group of wealthy Amanto, the future Tendoushu. Thanks to having a monopoly on planets and their Altana, it is they who conquered worlds for their control and research. This also led to the Tendoushu, and by extension the Amanto, eyeing Earth for its Altana.
It is unknown when the Amanto invaded the other Earth countries, but they did confront the country with the biggest Altana hole (a place Altana naturally leaks from), Japan, which at the time was under an isolationist policy. Led by the Inuisei, the Amanto threatened the Bakufu with annihilation if it refused to open its borders to the universe. Seeing how outmatched they were, the government capitulated to their request and signed unequal treaties, ceding power to the Amanto. Many citizens, especially among the samurai class, refused to accept this surrender and believed the Bakufu to be traitors to the country. This sparked a decade long civil war called the Joui Wars between the Bakufu and the Joui. The Bakufu, now under the control of the Amanto, received direct military support from alien mercenaries. Under orders from the Tendoushu, the government initiated the Kansei Purge in response, a brutal campaign of political repression which killed thousands. For the next ten years until the manga/anime's present day, the Tendoushu consolidated their power in the country and an influx of Amanto and their cultures entered the planet.
Though the Joui were ultimately crushed, resistance never fully disappeared. Over the following ten years, the Tendoushu solidified control and Earth became a hybrid of old and new. In Edo, now the capital, futuristic spaceports and wormholes coexist with traditional wooden houses and modern skyscrapers - a visual reminder of a world forcibly transformed by foreign occupation.
Races[]
There are countless Amanto races shown that go unnamed but these are the known ones shown in Gintama:
The Amanto invasion is based on Japan's forced opening of its borders after two centuries and a half of isolationism by the more technologically advanced country of the United States, followed by the European nations during the mid 1800s. This event led to a series of unequal treaties called the Ansei treaties, in which Japan was coerced into ceding political and economic control without reciprocity, mirrored in Gintama by the Bakufu’s capitulation to Amanto demands under threat of annihilation. Just as in history, these treaties stripped Japan of sovereignty and empowered foreign interests, reflecting how Earth’s leadership in Gintama becomes subservient to the alien Tendoushu and other imperial forces.
Some readers also interpret it as a satirical allegory of the US Occupation. In this reading, the Amanto parallel the postwar American presence, with their imposed unequal treaties, bases displacing the local people, foreign troops garrisoned in Edo, and a dependent consumer culture.
