Demons

Here's my first theroy guys. So what if the new enemies are souls consumed by darkness, not soulless or dis-souls but demons.

How it's created :
Master xehanort was possed by the strongest demon of darkness. this demon has complete control over master xehanort and is using him to flood souls with darkness creating these demons. My proof for this is when what master xehanort said in the trailer.

Master xehanort: he has become a demon of darkness. [this is the demon talking]
Master xehanort: please correct my mistake [master xehanort gains control for a moment to tell terra this.]

How the demons was destroyed:
This new enemy no longer exist, so how was is destroyed? Because the demon in master xehanort was the only one who could create them. master xehanort's demon posses terra later on becoming the younger xehanort, but he lost his memory so xehanort can't remeber how to create them. So the heartless that were created later on were stronger than the demons and wiped the ones that remained. and there was no way to make more.

end of theroy.