That sounds pretty interesting. It does seem like it could be a bit strong to start off with. Flying is considered something of a special ability in KH, so I don't know about that. But jumping really high and other acrobatic stunts are very doable. Maybe just focus on the constructs and shielding to begin with, and we can think of other powers to unlock later.

I think it's a good idea to have a special focus or weapon as well. We're not necessarily going with keyblades but each character would probably have a unique weapon based on their past life.

As to whether we are villains or heroes, we're positioned in a fun way to be somewhere in the middle. We're definitely opposed to the darkness after losing everything to it. On the other hand we spend most of our new lives in the worlds of darkness, and we're well-suited to it compared to regular humans. Having no heart makes us less vulnerable to darkness, and less appealing targets for mindless heartless. But we also oppose the warriors of light. We see them as naïve and tragic fools. In trying to save their worlds, they doom them to destruction (like we did.)

Our guild of nobodies is trying to carve out a third position in the grand conflict between light and darkness.