The Region of Unova was once a grand place, where people and pokemon lived together in harmony. The two worked together to help create a bright and beautiful future for all, a future where everything was perfect.
But that was before Vladislav.
Vladislav, a Darkrai, came to Unova in chains when a group of poachers took him to sell on the black market. In a fit of rage, he killed his captors and fled into the wilds of the region. There, he rallied a massive army of pokemon into a group he called Oblivion. Oblivion devoted itself to one goal: erraticating the humans of Unova. Within weeks, The army of Oblivion had completed many successful conquests, seizing towns and killing any humans that lived there. Any attempts by humanity to resist was futile, as the sheer scale of Oblivion's military could crush whatever stood in the way of Vladislav's ultimate ambition.
Within a year, the armies of Oblivion had seized control of the entire region, and the last humans had all been hunted down and killed. The sounds of the bustling cities replaced by the terrifying cries of Golbats and Skarmorys as they patrolled the air above Unova. Oblivion's huge and powerful military had stopped all attempts to get in or out of Unova, effectively sealing it off from the rest of the world. Vladislav now stood at Oblivion's head, ruling as emporer of Unova.
Yet there was still hope...
Not all of the pokemon in Unova wanted to submit to Vladislav and his massive army. These pokemon called themselves the Unova Alliance, and together they fought to overthrow the tyrannical emporer and return Unova to the way it once was: peaceful and gorgeous, with pokemon living alongside humans in mutual companionship.
News of this eventually reached Vladislav, who has now devoted himself to a new goal, stamping out the Unova Alliance and everything they stand for. This escalated to a full-scale war, a war known as the Pokelypse.