While it is currently the eleventh most populous country on Earth, Japan's population is one-third elderly, and low rates of marriage and childbirth are expected to contribute to a significant population drop in the next half century. Recent reforms to protect the rights of immigrants have been established to counter labor shortages.

Japan's relations with other nations is at times strained due to a history of military action and colonialism coupled with tacit or official denial of past atrocities, especially straining the nation's relationship with South Korea and China; ongoing territorial disputes with these as well as the Russian and Taiwanese governments also affect international relations. Japan's losses in World War II led to a formal restriction of the nation's military forces, although ongoing clashes between hawks and doves in the government have led to changes over the past few decades, especially under the long office of former prime minister Shinzo Abe, a notorious right-wing nationalist with familial ties to the 'Unification Church' cult and who advocated for increased militarization.

Having the third-largest economy in the world by GDP, Japan is widely seen as a leader in technology (especially the automotive industry, video games, and space research), although its former dominance in consumer electronics has been in decline. Japanese comics and animation—respectively, manga and anime—have had a growing influence on global entertainment culture, even seeing import off-planet.

The nation's long history of formalized martial arts, spiritual traditions, and presence of nonhuman entities have combined with historic links to alien civilizations such as the Oni and Juraians to produce a population boom of metahumans, including the recent reveal that a large group of Senshi reincarnated as Japanese citizens.