All of Vanitas's current existence could be resumed as: attempts.
Attempts to get out of Sora's light, to go back and show those pathetic little Heartless just how havoc was wreaked.
Attempts to get Ventus to quit influencing the boy – Vanitas would never get himself out with all that warmth and unusual emotions around.
Attempts to get what darkness he found under his rein – hey, maybe Sora would get better with a couple of dark skills… not to mention, Vanitas got to go out and play.
But Vanitas wouldn't be stuck here if they had been successful, right?
Back to the drawing board…
Xion's existence – or lack thereof – could also be simply put as attempts.
Attempts at reconnecting with what there was of Roxas still here, lurking alive in Sora.
Attempts to finally walk back into anyone's mind, to gain a bit of what Xion had willingly lost…
Attempts to figure out just who was that shadow with bored gold eyes, smirking and whispering soft promises of the dark to the boy Xion had gone to such ends to help.
And, needless to say – attempts to shut him up. Xion would not have her forgotten sacrifice go to waste – she swore as much when she faded.
Vanitas would like to know why exactly there was an extra specter here. It wasn't the same girl as previous – thankfully, there was no glare from the light.
Vanitas would like to know who the faded shadow was as well. And why she made to snarl and complain at him so – yeah, he wasn't including her in his schemes…
But why would little blackbird want to keep the lights on? She'd be just so free, like the rolling waves, if someone would just dull down Sora a little…
Vanitas would like to know why is he caring about little bird-shadow so much. Maybe it has something to do with the Keyblade she keeps almost-waving in his face.
Eventually, Vanitas got bored of simply trying to darken up Sora suitably. Xion – no, blackbird – was beginning to be more entertaining…
He enjoyed her attempts to bring some light into him…
Funnily enough, they might work this time round. If Vanitas gets bored enough, that is.