This is why I don't really care about KH in matchups, the profiles are a bit unclear about things.
Now, about nobodies, there's a little detail that is being overlooked: when the heart is removed ,the body fades into darkness, only to reform later in the Realm of Darkness. And how has the realm of darkness been described as?
"Secret Ansem Report 06
My choice to befriend darkness here in the midst of nothingness was a sound one. The moment I stared straight ahead with a calm heart, neither rejecting darkness nor fearing it, I gained a newfound power.
A superhuman power - the power of darkness.
It is likely Xehanort and the others were enraptured by this power, eventually becoming its prisoners.
I do not intend to allow my heart to be devoured by the darkness as they did, of course.
With this new power, I uncovered a "Corridor of Darkness" that connects the realm of nothingness to the outside world. While it is still difficult to come and go as I please, my banishment is now a thing of the past.
To deceive Xehanort and my apprentices, I first used my power to change form before returning to the realm of light.
As I suspected, Xehanort had become a Heartless.
Under my name, he commanded other Heartless in quests to snatch away the hearts of many different worlds. At the center of the hearts Xehanort had stolen was "Kingdom Hearts," which attracts tremendous darkness to itself and attempts to send any and all matter back into its depths.
The other five have disappeared. Have they become heartless like Xehanort?
Or did they vanish after Xehanort exploited them?
I became familiar with an unusual "entity" while pursuing the truth.
.*It is the soul and body that remain when a being loses its heart.*
When a Heartless is born, these entities disappear from the realm of light, to be reborn as entirely new beings in a completely different realm.
Secret Ansem Report 07
While beings born of darkness and those lacking hearts may find them convenient, it is dangerous for others to make much use of the corridors of darkness. Darkness erodes the heart.
In search of a place to proceed with my research and planning away from prying eyes, I found myself in "Twilight Town." It is a quiet village, forgotten in the chasm between light and darkness. I situated myself in the basement of an abandoned mansion standing beyond the woods.
My underground research resulted in one new discovery after another.
When a Heartless is born, the *body and soul* left behind are reborn into this world as a different being.
They possess different intentions than their Heartless brethren, and while it is unclear what these sentient "Things" are after, it would appear they are responsible for much bedlam in the world.
My erstwhile friend the King and his subjects, along with a hero wielding the keyblade, are battling the Heartless even as a new threat approaches.
This new threat... they have given themselves a fitting name, I suppose.
These non-beings: "Nobodies."