Talk:Noro/@comment-26974774-20160106122655/@comment-27204325-20160115103130

^ Again, the only trouble with the theory of RC Cells themselves being a parasitic lifeform is that, as far as we know, they aren't lifeforms. They're cells. They're apparently benign and useless in humans, but in ghouls they form various kagune structures, just like myocytes form muscle tissue.

But if you had, say, some tribe that regularly practiced cannibalism and ended up with abnormally high RC levels, and over time developed an organ to contain them to prevent ROS, that could be a factor. And it could also have been initially spurned on by some parasite, bacteria or prion, but that organism would just be the catalyst, I think, not something inherent in the genome. But we've seen with ROS itself that when RC Cells run wild in humans they develop kagune like structures, so humans and ghouls are clearly very closely related, and Ghouls may just be a very specifically adapted member of that family.