Time Passing of Arregeas

The magical energy source, a densely concentrated current of magic created by the elves of Segiirnersis, starts getting out of control. It is sucking magic into itself, causing the death of first trees and wildlife in the larger area, and then the elves start to die as well. The reason is a magical imbalance in the environment that sucks the life out of nature.
In a grim and desperate battle, not only against magic, but against some of their own people (e.g. Relaar), Kyrtaar, Taalyt and Diia with the aid of Selakiir, release the energy source from its confines to reestablish balance in the magical athmosphere.
Kyrtaar brings the ultimate sacrifice and loses his ability to wield magic. Taronlagiir is in shambles and most of Segiirnersis uninhabitable, which causes most elves to flee the country. Some migrate east and, stripped of their magic, become mortal, others join their brethern farther south, but a small group stays. Kyrtaar is among them, and it is him and others that, much later, would make their way over the Sunkissed Peaks and found Kaat.

Estishya, after long meditation, achieves the power to bend magic to her will and becomes the official ruler of the realm, which before she had been in all but name. With overwhelming support she takes up the crown of the woodlands and names her realm "Estira", "Realm of Estishya". Even after her death the realm would keep this name in honour of its founder and the first elf to bend magic to their will.

Died in a great battle wielding so much magic it tore her apart.

The dwarves, after a long period of wandering from mountain to mountain, never settling anywhere because none of the places had been fitting, dig deeper and deeper into the mountain Greimo and find an ancient hall, to wich passage had been blocked before. Seeing the marvellous architecture, something so grand the dwarves themselves hadn't been able to make yet, they call it the Crown Hall and decide to settle there for good. Their leader, a wise dwarf woman is crowned queen and rules from the Crown Hall, which becomes the heartpiece of the mountain and from where the dwarves start digging a vast network connecting Greimo to older mines they'd abandonned before.

Kaat was founded on this day.

A gret hurricane in the Eastern Plains that leveled everything flat and killed almost anyone who lived there. Before the Breath of Calamity there had been a bustling nomad culture with a glorious city as an anchor point in the middle of the Plains. Many are convinced that the hurricane had been some kind of divine rage/punishment. It's the reason why the month of Stormbloom is called that. Before it was known as Bellring, because the almost constant breeze had made the bells hung out for Dahebanuu ring constantly.

According to legend, the Mirkhari King, Bermir the Terrible, is responsible for the creation of the Grey Barrens, a magic dead spot. The story goes that Bermir was cursed by three draconian goddesses and found his demise in the area that later became the Grey Barrens and that it's his tomb among the thorns that sucks the magic out of the land. The legitimacy of this incident, however, is highly disputed. This day marks his death date, but it would take some more time until all land around his supposed tomb would become the wasteland it is today.

The swamp where King Bermir had allegedly been entombed for the better part of 200 years has dried up entirely and beckome a rock-ridden wasteland entirely devoid of magic.

After multiple days of earthquaqes and smoke rising from the top of the mountain, the Fiery Mountains' crown jewel errupts with huge force and ravishes the land in its vicinity. Rivers evaporate from the sheer heat and ashes cover the earth in a grey shroud of death. Out of those who didn't evacuate, few survive.

After a period of war, the three nations Miali, Hatnar and Oze become allies and bound together to become one country: Mivian.