Dark types are viewed by most as evil. From the "disaster causing" Absol to the "evil" Spiritomb.

But there are the few who want to disprove this, and Gwen Lichtenberg is one of them. Always fascinated by Dark type Pokemon, Gwen has decided to go out and prove that not all dark types are bad. Although, having a Spiritomb as your main Pokemon doesn't help things.

And then there was the whole "Legendaries getting together and deciding to teleport a vast majority of the Pokemon, along with some humans" thing...