“The Cataclysm was not one event, it was many. Lands rose and fell. The sky rained fire, ash, and worse things. The seas rose and then retreated. It is a miracle that any of us are still here.” ―Apollyon

The Great Cataclysm or simply the Cataclysm was a natural, planet-wide catastrophe that struck the world of For Honor with a series of apocalypse-level events. Prior to that, the history of For Honor paralleled the real world like a mirror, so the Cataclysm is the single main catalyst behind the story of the setting.
Overview[]

The Cataclysm in all its forms.
The only solid information we have is that the Cataclysm occurred somewhere around the year 1000-1199 A.D.[1] The exact events are unknown, but records describe earthquakes of immeasurable magnitude, meteor showers, and massive volcanic eruptions. The topography of the planet was changed and entire civilizations were wiped out. The fact that anyone survived was nothing short of a miracle. Those who did survive would come to face a world different than the one they knew before. Over time, their culture and even their technology would be influenced by the changed world and lack of resources.
Knights Aftermath[]

The Knights of Ashfeld live in a land that constantly reminds them of their past. While the land is stable, tremors can still occasionally be felt. Many locations had to be abandoned since the ground beneath it was deemed too unstable. While locations such as the Cathedral have survived with mere cliffs and geysers forming around it, many other locations were not as lucky. The Iron Legion traces their roots back to a Great Empire that existed beforehand. For a while, it was believed that this empire was wiped out during the Cataclysm. It survived, albeit barely.
Viking Aftermath[]

The Vikings of Valkenheim can trace their lineage back to a great Nordic Empire that was swallowed by the unstable earth, forcing them into an exile from which they would return centuries later. Though the land has stabilized, massive volcanic eruptions still occasionally blot out the sun and bring about eras of famine.
Samurai Aftermath[]

The Samurai have had it the worst after the Cataclysm. They realized their island country was unstable and so they packed up as much as they could onto a fleet of ships and sent them out in search of safe harbor. Plants, animals, technology, they brought as much as they could on their arks. That is how they came across the Myre. It wasn't paradise but it would help them survive. They sent word back to their homeland but found that it had been too late. Their homeland had been swallowed up by the ocean.
Wu Lin Aftermath[]
The landmass of China was not torn apart or sunk like it was for the other three factions. But the Cataclysm decimated their society. While the Great War raged, China descended into hundreds of years of civil war. During this age of chaos, the Wu Lin has risen to become the most prominent faction in that civil war. But, like the Great War, there is no end in sight for the Civil War. So those torn by war and tragedy headed West, each for their own reason for travel.