Dawn War

In the Legendaria, the Dawn War was a massive conflict between the Gods and Primordials in the early days of the Prime Material Plane's creation.

Causes
Since the beginnings of existence the Gods and Primordials have had a strained relationship. The Primordials, being the embodiments of entropy and destruction they were, made many Gods wary of their existence, seeing Primordials as an unbalanced force that needed to be put in check.

Shortly after the Gods formed the Prime Material Plane, Tharizdun, the God of Madness, convinced the Primordials to wage war on the Gods in a bid for control of the Plane. Tharizdun used the Dawn War as a distraction to give him time to form the Abyss without intervention from his fellow Gods. This act by Tharizdun is known as the First Treachery.

The Invasion
While the planet of Ūnun was still being formed, the Primordials ambushed the Gods in an attempt to catch them by surprise. The Gods were able to quickly react, and a massive battle ensued.

During the fight, it is said in his arrogance, the dragon god Io engaged in a brutal duel with the Primordial Erek-Hus; The King of Terror cleft Io in two, but before the Primordials had even a chance to celebrate his victory, the two halves of Io rose up as Paladine and Tiamat, who united to slay Erek-Hus in turn.

The Primordials realized that this was not a fight that could be one in a single battle, and decided to retreat and regroup. The Gods realizing their fears had come true, began to put aside their differences to combat the threat.

It is believed that the location where the invasion began is where the continent of Kavoy would later be formed, and the interference of the Primordials is what led to the greater influence of the Elemental Planes on the region.

Shadow Epoch
The war waged on for ages, until the primordial known as Dendar the Night Serpent swallowed the sun, leading to what is called the Shadow Epoch. Realmspace became shrouded in complete darkness, and the purpose of the conflict seemed lost.

The Primordials and Gods agreed to meet to come to some kind of terms, seeing as how neither would get what they wanted out of the Plane. However during their peace talks, the Primordial Rorn, notorious on both sides for his violence and anger, flew into a rage and killed the goddess Mystra, one of the most beloved of the gods. The Gods saw the attack as a trick by the Primordials, and reengaged with them.

The two gods of war, Kord and Bane, worked together to restrain Rorn. Pelor struck the killing blow, and the power of the sun god and the blazing rage of Rorn combined to form a new sun in place of the old. With the war back on, the Gods sought to totally annihilate the Primordials for their hubris and the damage they caused.

As the tide war continued to shift in favor of the Gods, the Primordial called Ubtao approached them with a deal. In exchange for his preservation, Ubtao offered to reveal the location of Glaur: a massive fortress constructed by Nehushta to act a front for the Primordials in the war. The Gods were skeptical of his offer, so to prove himself Ubtao revealed one more piece of information: the god Zehir had learned of the invasion before it occurred, and offered his services to the Primordials' cause. He acted as a double agent, and most notably it turned out, poisoned Io before his battle with Erek-Hus, weakening him. This ultimately backfired when the two halves of Io returned as Paladine and Tiamat, but Zehir continued to work against his fellow gods throughout the war. Upon the accusation, Zehir attacked Ubtao, and the two battled for some time, before Ubtao killed him. The Gods, pleased with a deal and believing him honest, agreed. The reveal of Zehir's plot became the Second Treachery.

The Gods attacked Glaur shortly after, slaying many of the Primordials including their two remaining leaders, Miska and Nehushta. Ultimately, the Primordials finally decided to flee, and the Dawn War was won.

Aftermath
While the Gods could not slay all of the Primordials, they killed many. Eventually the few remaining Primordials fled back to where they came from, banished from the Prime Material Plane. The Gods reclaimed their land, and sought to rebuild it together.

Following Mystra's death, Corellon took her place as the God of magic.

When it was discovered that Tharizdun was responsible for the conflict, he was imprisoned by his fellow Gods in a pocket realm called the Void, to be kept there forever.

While the Gods often did not all see eye to eye on things, they united to reform the Plane, and from their unity came the mortal races, and seemingly, peace. However, this would not last, as inevitably the Third Treachery would alter the course of history forever.

Participants
It is unknown just how many Gods and Primordials participated in the Dawn War, as many were likely slain and forgotten to time. However a number of both are known to have been a part of the conflict, and are listed below:

Gods

 * Avandra
 * Bane
 * Corellon
 * Erathis
 * Garl
 * Gruumsh
 * Ilmater
 * Io †
 * Paladine
 * Tiamat
 * Ioun
 * Kord
 * Lliira
 * Lolth
 * Malar
 * Melora
 * Moradin
 * Mystra †
 * Pelor
 * Raven Queen
 * Selûne
 * Shar
 * Sune
 * Torog
 * Yondalla
 * Zehir †

Primordials

 * Achazar †
 * Akadi
 * Arambar †
 * Dendar
 * Draunn †
 * Dur-Baagal †
 * Erek-Hus †
 * Gargash †
 * Grumbar
 * Istishia
 * Karshimis †
 * Kossuth
 * Maram †
 * Maegera †
 * Miska †
 * Nehushta †
 * Petron †
 * Rorn †
 * Telos †
 * Ubtao