The Great Disaster is an event that happened two hundred and fifty years ago, 50 years before the Solar year 198, with the world mostly consumed in flame, many nations destroyed, and most of the planet rendered uninhabitable. The survivors took refuge in the Tokyo Empire, which remained mostly stable during the period despite losing some of its landmass. The Tokyo Emperor Raffles I establishes the faith of the Holy Sol Temple as it and Haijima Industries developed the perpetual thermal energy plant Amaterasu to power the country. In Year 198 of Tokyo's Solar Era, special fire brigades called the Fire Force fight increasing incidents of spontaneous human combustion where human beings are turned into living infernos called "Infernals". While the Infernals are first generation cases of spontaneous human combustion, with more powerful horned variations known as Demons, later generations possess pyrokinesis while retaining human form. The Fire Force was formed by combining people with these powers from the Holy Sol Temple, The Tokyo Armed Forces, and the Fire Defense Agency, and is composed of eight independent companies.