The Great Cataclysm (大災害, Daisaigai) is an event that happened two hundred and fifty years before Year 198. The incident involved flames exploding around the world, devastating it and leaving most parts of the planet uninhabitable. Continents were torn apart and some nations were utterly obliterated. As a result, survivors fled to the Tokyo Empire, which remained mostly stable during the period.
The flames that brought this destruction upon the planet was the Adolla Burst. The Evangelist chose Japan as the source of the Great Cataclysm because it had a large number of atheistic people and thus no spiritual root. This made it easy for the collective unconscious to develop and flow through people.
The Great Cataclysm altered the very structure of the world, distorting its visage to that of an anime/manga world, giving animals the potential to learn how to speak, and putting people at risk of Spontaneous Human Combustion. When Shinra Kusakabe saw the pre-cataclysm world and the people of the past, he knew that both the people from back then and the people of the current time period could both be classified as humans and had all the necessary characteristics needed in order to be considered human, but he also noted that "strange" does not even begin to describe the people of the past.
It was revealed by Sumire that the Great Cataclysm had actually failed to burn everything away completely due to lack of Pillars as well as the lack of strength of them. Each of the Pillars embodies a different negative human emotion; madness, passivity, apathy, rage, destruction, fear, disgust, and despair. These emotions, born from humanity themselves, are what fuel the fires of the Great Cataclysm. As such, the progress of the flames can be countered by positivity and hope.
Notably, the negativity of one powerful individual, such as Dragon, outweighs the positivity of multiple weaker individuals and can keep the flames raging, even if the masses maintain a strong sense of hope.
After the Cataclysm, The Holy Sol Temple, Haijima Industries and Vulcan's ancestors, under the guidance of Yona, who had take the place of Raffles I, collaborated to create the Amaterasu power plant, enabling sustainable power for Tokyo to utilize nation-wide. This power let the Empire develop further and allowed for more migration from the outside world. This lead to cultural changes within the Empire, such as it becoming customary to refer to others by the first names as opposed to their family names.
- Chapter 51, page 6
- Chapter 51, page 8
- Fire Force Manga: Chapter 253