I have read the entire series.
Ch.251 has the SW clone.
I saw parts of the chapter years ago.LOL.
Theres body expansion(no process) that happens in a dream.
Nube and the fox guy made child clones of themselves which are incapable of dying, they had an ability that allowed to separate their individual body into hundreds of smaller ones.
There is a sequel of sorts from the same guy.
Reibai Izuna, it appears that the story focuses on Izuna whos an exorcist in training from the nube manga.
I have been looking for raws but sadly nothing.
Can someone help.
http://www.mangaupdates.com/series.html?id=31336