yeah, the overly beaten bush of BBS. This is not exclusive to my theory I'm looking for anyone who has anything to say about the Unbirths, because to be honest I've been losing sleep lately.
Okay, I've heard this a few times before and I've repeated it even more often. Corrupt light.
Light,Dark, and Twilight. We all can easily figure out what Light and Dark is but Twilight is a more complex subject. Simply, it is an instance when Light meets Darkness. That's exactly what I think an unbirth is. A physical manifestation of Darkness combining with Light. It's difficult to process, I know. But just think. It would pave a way toward the creation of heartless. and naturally nobodies.
My second idea, Kairi's grandma's story. People fighting over the light creating darkness. I don't have the exact material so bear with me. I still think that Unbirths are what ever is left over of the first people in the story. When the darkness in their heart was created, they completely lost the original form and become unbirths. So great number of Unbirths in BBS, TAV and others destroy all of them no more Unbirths left over in KH1 or others. Okay, like I said a UNbirth is from the creation of darkness, where a heartless is from existing darkness taking over. Unbirths created the darkness that led to the creation of heartless.
Please ask any questions if you are confused. Praise much appreciated.