IF i'm not wrong, i remember that it's said in Days and KHII that the organization xiii was a selection of special nobodies, yknow? like, xemnas chose the people that could be manipulated into becoming vessels for xehanort... but it was never said that they were the only special nobodies to ever exist i also remember from kh re:com that they mention special nobodies can turn into a dusk, so maybe those special nobodies that we don't see/hear about turned into dusks since they didn't have anything "holding" them
