Most races seem to agree that the dimension of Pandor was created by a long dead race, but King Kirvas hints that the dimension is his homeland, which may mean that it was inhabited by, or created by the race that the King belongs to. This is all speculation, as the King rarely audiences with the members of the other races.
The plane was first discovered by the Egreians, who once inhabited the planet of Egrei, but have completely moved into the dimension of Pandor. It was discovered when miners were digging into the core of their planet, when they discovered a huge chamber, with a glowing light coming from the centre. The miners investigated, but were never seen again after entering the portal. The Egreian government sent another group, this time a highly equipt military team, of which only one returned, stating they had been massacred by a strange man upon entering the portal, of which their weapons had seemingly no use against. The Egreian government then sent a large part of their army into the portal, eager to avenge the deaths.
However, upon arriving they discovered a barren wasteland, with no mysterious being to be seenm but it was only after exploring for some time they came across him. The being apologised, and informed them that he had not had visitors for a long, long time, and began talks with the race's leaders. The being, believed to be King Kirvas, explained to the Egreians the tragedy of his race, stating "We were destined to rule the stars, but we didn't know that first we must rule ourselves." These words have made the races of the galaxy to believe that his race may have died in a civil war, or some unseen foe.
The King then gave them an offer, he invited them to join him in the plane, and if they served him, eventually they would be the most fearsome force in the galaxy. The Egreians, who were confused as they had never achieved space flight, were not aware of the other races of the galaxy, and did not believe that their were any other empires. However, the King took the leaders to a special chamber, which showed all the empires that had a portal on their planets, with some of them inhabited by alien races, while others were barren wastelands, pocked with craters.
Shortly after, the leadership announced that the entire Egreian race would move to the Plane, and would live in prosperity until another race discovered the plane.