Era beginning/end
The birth of the Greatwyrms and their war against the Primordial Elementals. Leading to the establishment of Mundus as is.
Legends state that before there was anything of matter in this world, there was a being who was all and nothing. This being would be referred to by scholars as The First (or Io). It is said in an act of pure random chance, The First divided into two beings of pure essence known as Ethera The Radiance and Nihilus The Entropic. These two would come to represent dual aspects of existence, Order and Chaos, Creation and Destruction, The Beginning and The End.
In certain ancient religions of this world it is said that these two beings inevitably clashed. The blood that they spilled would go on to form the Outer Planes of the Aether and the Nihiloth, and their corpses formed the Material Plane. But there are those who actually refute this, believing that they were actually partners, and that the creation of all of the planes was an act of love resulting in their union.
At this same time, additional godlike beings would begin to emerge from the Aether and Nihiloth. To historians, they would become known as Aetherians and Nihilans, the first gods. These two pantheons were diometrically opposing forces, each seeking the others defeat in order to control the burgeoning new world that formed beneath them.
It is said that residual energy from this first conflict created the first sparks of what would eventually become known as Arcane Magic. Some of these sparks would converge into the very first mortal beings of the Material Plane, the first Dragons. The Two Dragons Palladrex and Timora would rise as leaders over all of their kind.
Palladrex was said to have seen the seeds of conflict beginning to spread between the Aetherians and Nihilans, and desperate to prevent their constant battles destroying this fledgeling world, he comissioned the greatest Dracocnic mages to band together to create a powerful arcane barrier that would become known as "The Veil". The Veil prevented the entry of any beings not originating from the Material Plane.
The Material Plane also began to emanate a magic of its own, completely separate from the Arcane Magic that pervaded the realm. This "Deep Magic" resulted in primordial beings known as Titans, powerful beasts who were the anger of the world given form. These titans arose and challenged the dragons, believing their existence to be a blight that would result in untold catastrophe. The dragons were able to subdue this threat, with the fallout of this war giving rise to the various continents as a result. These primordials are said to have spawned the early giants and the numerous elemental creatures of the world from their deaths.
After the fall of the titans, a new conflict began to emerge between the Palladrex and Timora and their spawn. Desperate to prevent a potentially world ending conflict, an event known as the Draconic Exodus took place. In it, the various Dragons absconded from the great city of Irral Taoul for various dwellings across the world, with their own kind following suit. It is said any time a Greatwyrm has been seen since, it either portends of either a prosperous era, or imminent doom.