It's been thought that the Heartless did not come into creation until Xehanort's experiments in Radiant Garden. This would mean AFTER the events of BBS. This is true. However it is also true that Heartless have existed before BBS as well. Pay close attention now:
The Heartless have existed for as long as humans have.
Heartless are created from the Darkness in people's hearts. So as long as people exist, so will the Heartless. The only way Neoshadows can be a plothole is if prior to BBS, everyone's heart was filled with nothing but light, thus there would be no darkness to create Heartless. But this is impossible as it is shown in BBS that Terra has darkness in his heart, as does Ven at one point.
Neoshadows are Pureblood Heartless, meaning they are born directly from the hearts of people. It is safe to assume that EMBLEM Heartless did not appear until Xehanort's experiments.
We are talking about two separate groups of Heartless here.
I'm sure this has already been brought up, but I thought I'd give a more clear explanation.
The Heartless have existed for as long as humans have.
Heartless are created from the Darkness in people's hearts. So as long as people exist, so will the Heartless. The only way Neoshadows can be a plothole is if prior to BBS, everyone's heart was filled with nothing but light, thus there would be no darkness to create Heartless. But this is impossible as it is shown in BBS that Terra has darkness in his heart, as does Ven at one point.
Neoshadows are Pureblood Heartless, meaning they are born directly from the hearts of people. It is safe to assume that EMBLEM Heartless did not appear until Xehanort's experiments.
We are talking about two separate groups of Heartless here.
I'm sure this has already been brought up, but I thought I'd give a more clear explanation.