Okay this is something i never understood. If i understand the story right Xemnas and Xehanort's Heartless (and the first organization members) were created when Terra/Xehanort extracted his own heart after doing experiments on hearts and regaining some of his memories i think that is correct please tell me otherwise, but at the end of Terra's story in BBS Xehanort extracted and entered Terra's body shouldn't that have created a Nobody and a Heartless or did it not since the his heart entered another body? also how can Xemnas and Xehanort's Heartless destruction resurrect Xehanort when they were created when Terra and Xehanort were the same person? shouldn't Terra/Xehanort been resurrected instead?
This was probably answered in the games, even thought Kingdom Hearts is my favorite game series of all time i might have not picked that up when i was playing