The Legends Before Time

The Legends Before Time is a Pokemon past story written by Gregory Tyson (yours truly). It is said to take place long before the events of the Type Unity Law, Pokemon: Beginnings and Pokemon: Unlimited. The story itself involves a Wobbuffet named Waffle, who is Arceus's (known as "Lord" Arceus) assistant that helps out with many legends (statuses) at the Palace of the Heavens at the time before their sudden demise.

Story
Acording to Arceus, before the arriving of the legends and myths known today, there was once another world in which he and 17 other Gods birthed by the Omni Egg were created to maintain it. However, there were disparities among the gods wanting to prove which type was stronger and soon entered a war. During this, the common Pokemon of the old word grew corrupt by the influence of the gods and soon the war ended, leaving Arceus as the only survivor. In response to this, Arceus transformed the other 17 into Plates, which he used to create the new world after destroying the old one. Among the creation of the world, he had three sons from a mysterious mother, which were Dialga, Palkia and Giratina.

After establishing the new world, he went to create more Statuses, which would serve as his forces. However, his youngest son Giratina would cause trouble among the common Pokemon, which forced Arceus to ban his son into the Chaos Realm, ending the chaos that would ensue.