Xehanort and the heartless begin to attack all the disney worlds and Mickey and Yen Sid realise that Even with all of the current keyblade wielders they won't be able to defeat his forces and so Sora(or Riku I haven't spoiled myself about Kingdom Hearts 3D) Donald and Goofy all have to go out and recruit the Disney heroes Mass Effect 3 style before going for their final siege on whatever world Xehanort resides with all the other heroes as well.
To be honest I'm just trying to think of a way that it could end on a battleground which is the only way I can really see the series ending. The only other option I can think of is if a crap load of new keyblade wielders come out of nowhere and start beating the crap out of all the heartless (and nobodies)
Xehanort and the heartless begin to attack all the disney worlds and Mickey and Yen Sid realise that Even with all of the current keyblade wielders they won't be able to defeat his forces and so Sora(or Riku I haven't spoiled myself about Kingdom Hearts 3D) Donald and Goofy all have to go out and recruit the Disney heroes Mass Effect 3 style before going for their final siege on whatever world Xehanort resides with all the other heroes as well.
To be honest I'm just trying to think of a way that it could end on a battleground which is the only way I can really see the series ending. The only other option I can think of is if a crap load of new keyblade wielders come out of nowhere and start beating the crap out of all the heartless (and nobodies)