/vr/ - Retro Games

I would say Cloud of Darkness or Necron, as they're both emissaries of the void. If they had their way, existence would be nullified completely. Other villains might go as far as to make themselves into despotic rulers, or destroy only a single world. I don't think the void would stop there.

In terms of raw prowess, I guess it's a toss up between Kefka and the Emperor of Palamecia. Both end up destroying the world, and the Emperor of Palamecia goes on to dethrone Satan and take over hell while he's at it. But when are they satisfied? I think the Emperor of Palamecia merely wanted to be a despotic ruler, whereas Kefka's diminished sanity drove him into a state of complete nihilism. After destroying the planet, he possibly would have explored the cosmos in search of other worlds to destroy, until the universe had no further reason to exist.