The Planar Wars
Pantheon of Deities
In the beginning there were the five Titans, Salus Titan of Good, Malus Titan of Evil, Iussus Titan of Order, Chaus Titan of Chaos, and Medius, Titan of Balance. Driven by an otherworldy instinct, Salus and Malus challenged each other to a total of four duels. Both titans were evenly matched, and would only win with the intervention of Medius. He allowed each Titan to win twice, as was his duty to keep the balance in tact.
Upon winning a duel, Salus and Malus were given the opportunity to create offspring. However, the children were lifeless, and lacked a catalyst to revive them. The pairings of the four titans resulted in the Good and Evil gods, but with each iteration of the duel, the titans grew weaker. Medius, discontent and jealous of the other titans, took advantage of the accumulated weakness of them, and slew Salus and Malus. He casted their bodies away which turned into the Upper and Lower planes respectively. He took Iussus and Chaus as his wives, and created the Neutral gods. Next he slew his wives and and spread their remains throughout the Upper and Lower planes, creating the 16 planes of alignment.
Medius placed the other Titans’ children throughout the newly created planes. He used some of the residual magic from Iussus and Chaus as well as his own power to create the Inner and Transitive planes. Although there were all these planes, Good & Evil, Law & Chaos, he still was not content, for there was a lack of a truly neutral plane. Too weak to craft one on his own and survive, he decided that his final act would be to use his own body to create the Material Plane and its Echoes.
The result of this conflict are the Planes of Existence.