Sixth Umbral Era
At the end of the War of the Magi, Eorzea had become twisted and decayed after three hundred years of Magic-based war and destruction, the Aether of the land was almost completely drained. With the aether being so drained, the realm's elemental balance was greatly skewed, slipping everyday further and further towards water. Recognizing the damage that had been caused, each nation called upon its seers to look into the future of Eorzea, but all that could be seen was darkness and destruction. Thus did the Sixth Umbral Era begin.
Realizing the direness of the situation, the nations of Eorzea put their feuds aside and began working together to forestall the coming destruction, or at least delay it. The realm's imbalance towards water indicated that the coming destruction would most likely manifest in the form of a colossal wave or raging tide that would swallow the land. Knowing this, the nations were able to begin preparing by pooling their resources and creating command centers. These command centers were used to aid civilians in evacuation and escape. These command centers would come to be known as the first ever Grand Companies that the Eorzean Alliance would use as a basis when building their own. Amdapor began evacuating people to the north to Abalathia's Spine, hoping that the high altitude would guarantee their safety. The people of Nym who had not been affected by the Green Death sent the remainder of their navy out to sea to erect powerful wards and barriers to stay the coming tides in an operation that would come to be known as Operation Maelstrom.
During this time, while the Mhachi people assisted with fleeing and evacuation, they also secretly worked on another project; a massive ark that would be powered by their Void magic and imprisoned Voidsent and would carry their people and their livelihoods to the skies above, guaranteeing their continued survival. But in order to power this massive vessel, they would need to imprison an extremely powerful Voidsent. Thus, they summoned forth Scathach, the Shadow Queen. As one of the highest-ranking Voidsent, they would need an exceedingly powerful Voidmage to control her. The Mhachi people elected Cessair Blackwind to do this. Though she was vehemently against the plan, and the War of the Magi in general, she nevertheless agreed, recognizing her talents were needed for the good of her people.
When the tides finally came, the raging sea created waves unseen by any in the history of Eorzea before. The waters crushed coastal towns to rubble and wore them down to barren reefs. The lands washed over by the waves were left sodden and salted, where not even the hardiest plants were able to take root. Centuries later, when the waters receded, the people of Yafaem would come to find their once-beloved homeland had been reduced to nothing more than salt-clogged mires incapable of sustaining life. The home of the Nym was swallowed whole, and would be hidden for centuries, rediscovered much later and revealing the fate of those who were affected by the Green Death and sealed away to prevent the spread of the disease.
While the barriers raised by Operation Maelstrom succeeded in turning back the worst of the storms, they were unable to prevent the seemingly never-ending waves that followed. Whole cities were consumed, including Mhach and Amdapor. While a majority of the Mhachi boarded the ark, there were those who stayed behind to ensure its safe departure. Though they would perish in the Calamity, they died knowing their sacrifice would mean the survival of their people. This however was not destined to be the case, for as soon as the ark took off, Scathach broke free of her restraints, being far to powerful for even the most talented Voidmage to control. She made quick work of her captors, and freed the other imprisoned Voidsent, who proceeded to decimate the entire Mhachi population. In a desperate attempt to protect the outside world from their mistake, the last remaining Mhachi mages gave their lives to erect a seal on the ark, preventing any of the Voidsent from escaping. The ship would continue to float silently high through the skies for over fifteen hundred years before being rediscovered thanks to advancements in Airship technology, and being dubbed the Void Ark.
Those who chose to stay behind in Amdapor attempted to aid their people in escaping by using their White Magic to turn back the tides, however with the aether of the land being so depleted, they had nothing to draw upon to do too much for long. The last remnants of the nations escaped to the mountains, forming small settlements that banded together in a desperate attempt to survive. At the same time, Nyunkrepf Nyunkrepfsyn set out with a ship named Nyunkrepf's Hope, and used it to rescue any who had been washed away or unable to escape. Though this ship rescued a great many people, the tides would eventually create a wave that would smash the ship to pieces if it hit them. In a desperate attempt to save everyone, Nyunkrepf cast a powerful and ancient spell, teleporting the ship and all her passengers to safety, landing the boat amongst the peaks of Mount Yorn in Gyr Abania. Though the people were safe, they soon departed as the area was full of small hostile settlements that constantly battled for food and resources. They would set out for the The Northern Empty and eventually establish the community that would evolve into modern day Sharlayan.
When the waters finally receded, the surviving populations spread out all across Eorzea, searching for resources driven only by the desire to survive. Magic became forbidden, and the few remaining sources of knowledge, be they written or living, were destroyed, leading to a pseudo "dark age" for Eorzea. Eventually, the lands would show signs of growth and communities would begin to prosper again, with populations booming after a mass immigration from all corners of Hydaelyn. Finally the Sixth Umbral Era would come to a close, with many believing the land had suffered its final Calamity, having now endured an apocalypse-level event for each element.