Great Cataclysm

The Great Cataclysm was the extinction-level event that occurred over 1500 years prior to the events of the story.

Amatera Mountain
Even before the cataclysm, the People of Archaia worshipped Amatera Mountain. As a result, most of their settlements were around the volcano and on the land that is now the Stepping Stones. Then, without warning, the mountain erupted.

Result
When the cataclysm came, the top of the mountain split open, spewing lava and covering the sky with darkness. The earth shook violently and the ocean surrounding the mountains got so hot they began to boil. The Neck, the land connecting Tochi and Ylliad, broke apart, forming the Broken Neck. The land surrounding the mountain ended up permanently burnt, later being dubbed the Scorched Lands. Most of the People of Archaia were killed in the onslaught of fire and ash.

Legacy
For centuries later, the people of Tochi believed the Great Cataclysm to be the result of Amatera's wrath. They thought that Amatera had grown displeased with man and wished for their extinction. The only reason the world was not destroyed is that Rota sacrificed Themself to stop the cataclysm, thus dying in the process.

Trivia

 * The Great Cataclysm forms the basis of Galia's date system. With events before being referred to as Before the Great Cataclysm (BGC) and those after as After the Great Cataclysm (AGC).
 * As such, the main story occurs in 1549 AGC.