Sixth Umbral Calamity

The Sixth Umbral Calamity, also known as the Great Flood or the Calamity of Water, was a great tidal wave that consumed most of Eorzea at the end of the Fifth Umbral Era. It was caused as the result of the land's aether reserves being severely depleted from the War of the Magi, causing the elemental balance to be thrown heavily towards the element of Water.

During the Fifth Astral Era, the people of Eorzea fully embraced the arcane, and delved deep into the arts of Magic. Much like the way the Allagan Empire used technology to drive their society forward, the people used magic to elevate their lives, slowly forming various schools of magic that helped structure several different societies and cultures, like the Mhach and Amdapor. As each nation grew more powerful, tensions begin to mount, particularly when the Mhachi people mastered Black Magic and Void magic, and used it to attack their neighboring city-states. When the people of Amdapor developed their White Magic as a counter to the Mhachi, a truce was formed between each of the nations. This would not last, however, as military tensions continued to mount, until eventually all-out war broke out. Using their magic to decimate one another, the land began to warp and twist, the aether slowly draining from it. Eventually, all sides began to notice the effect the war was having on the land, and a temporary ceasefire was called.

Turning to their oracles and seers to understand just how bad the damage was, but all that could be determined was that the elemental balance was so off that destruction was guaranteed. Soon after, the tides began to swell and the oceans raged. This was the sign of the calamity that was to come. Begrudgingly, the warring nations set aside their battles in order to come together and find a method of stopping it. They set up task forces that would relay information to each other and help coordinate their various efforts, forming the first Grand Companies. The Amdaporians began searching for a higher place to escape to in order to avoid the rising tides, and the Mhachi worked on evacuation efforts, while also working in secret on an ark to shepard their people to safety using the power of Voidsent. The Nym, diminished though they were thanks to the mysterious Voidsent the Mhachi unleashed on them, turning their people into what would eventually come to be known as Tonberries, sent the remainder of their military out into the sea to establish protective wards and barriers to defend against the worst of the storms and waves in what would come to be known as Operation Maelstrom.

Unfortunately, it would all be for naught, as the balance of the elements would tip so far towards water that an all-consuming tide would wash over the land, destroying anything that it touched. The remainder of the Amdaporian people fled to Gyr Abania, while the Nymean people escaped to the mountain ranges of La Noscea. The Mhachi people tried to escape in their ark, however they were unable to control the power of the Voidsent Scathach, who was supposed to be used to power the ark, along with several other Voidsent. They all broke free and swarmed the people aboard, killing most of them. The remaining Mhachi mages used the last of their life force to seal the Voidsent in the ship so they couldn't escape and wreak havoc on the survivors of the flood. Centuries later, the ark would be found drifting silently through the Sea of Clouds, and was given the name the Void Ark.