[ Well that's no fun. Vanitas had been anticipating something of a fight. That's what the guardians are to do, right? Eradicate Darkness without so much as a provocation? Either way, he doesn't care for the fact that Riku has come to the correct conclusion so fast. Makes it less entertaining. ]

This place is an improvement from where I was. Why would I leave?

[ It's a snide comment, but it's not like Vanitas cares overmuch. ]

But who knows how to answer your question... No one can, unfortunately.