Dr Doom enslaved all pokemon and gen 6 was called Pokemon Doom. In the game you play as one of the protagonist and you spend the whole game cleaning up his palace and watching youre fellow friends get mercilessly whipped by Doombots. Every pokemon including Arceus would be at Doom's mercy. The pokemon history would be rewritten and Doom would be worshipped instead of legendaries. All legendaries would bow down to Doom and any resistance would be met with death.