Arima Kishou made a very "interesting prediction" that if Humans accepted Ghouls then at some point, all Humans would become Ghouls. And later on in Tokyo Ghoul RE season 2, episode 10, we see a bit of his prediction actually happening.
However, I don't undestand how Humans can be "infected" into being Ghouls, the Kakhous are the organs that produce the Rc cells so even if a human is exposed to RC cells that shouldn't expressly make them a Ghoul because they would still lack the organ that physically manifests the Rc Cells?
Also why is Kaneki's Dragon Ghoul form still active? The real Kaneki, who was the source of the Dragons RC cells was taken away so how can the Dragon keep producing Humanoid monsters (the dragon orphans) that explode to release "Rc cells"? Cause the Dragon is Kaneki's Kagune from mutation and Cannibalism right? I'm kinda like super confused.
Also, did Arima actually foresee Kaneki turning into the Dragon? If not then How could he make such a spot on prediction.
I dont read the manga and I also don't mind spoilers.