It was already starting in front of us since the beginning...
What makes me laugh is the fact V is threatened by Eto’s book about their dirt work with CCG. They think it will shake the CCG from the inside and their world. And don’t worry, I don’t bash Eto here, I am just making fun of V overall.
But if you look well since the very beginning and even before :RE even started. Kaneki’s existence was just enough to make Amon doubt because he didn’t know what to do with such a being. He would’t know how to treat him: as a Human or as a Ghoul?
He was someone who raised this question very soon but he kept his thoughts for himself. Aogiri only watched him spare Kaneki’s life and let him. Shachi thought it was even awesome from an Investigator’s part. A Human picked an interest in a Ghoul and ghouls picked an interest in this Human. Shinohara even stated it was a strange Ghoul to Kuroiwa but once again they were mere whispers in the dark. Perhaps this is the reason he let his son around Haise a lot.
And then you have Arima, dear Arima, who met Fura and Hinami, he met Eto, he formed bounds with Ghouls and Humans. You have Yoshimura and Ukina who fell in love despite being at opposite sides: Yoshimura worked for this organization and Ukina wanted to unleash the truth. Kimi and Nishiki dated. Kimi was accepted by Anteiku knowing they were Ghouls. Kaneki and Hide, Touka and Yoshino. Shuu formed a friendship with Chie Hori despite everything. It was already shaking but once again it was whispers in the dark.
It truly changed when Arima chose Kaneki as his successor to be the next Reaper but his true goals were well-hidden. Of course, he wanted to create the One-Eyed King, the one who will bring together Humans and Ghouls together. But the main bases were alread there: Humans and Ghouls met secretly.
Actually, I have this feeling Arima wanted to test who was ready to accept this Half-Ghoul within the CCG and who might be working with said Ghoul later. It’s fucked up when you think of it. Arima was already shaking CCG in the inside thanks to Kaneki. Arima knew Kaneki was able to create bounds thanks to his great kindness and his shining smile. But of course, Arima couldn’t go further: his hands were tied down and he had to pretend he still worked for V. It put some sense into Investigators and made them realize something: Ghouls weren’t that bad at all. Arima just put the bases on this Revolution within CCG. You really can see the extent of Arima’s indirect influence here.
Kuramoto and Sasaki talked a lot as colleagues but they were shown later having a strong friendship, Takeomi got along with the Quinx. Juuzou liked Haise a lot. Of course, trust Juuzou for that. Jouuzou had nothing against Ghouls: he was raised by one. Akira, despite everything cared about Haise and I am sure she will join him in his fight. Hirako knew Arima and his goals and had nothing against Haise at all. Fura trusted Arima and he wouldn’t speak dirty about Haise. He’s a good guy. Even Mougan didn’t have anything against Haise at all.
But of course, you need something stronger to shake this organization. You need a stronger help. Eto, of course, published her book and it provoked a tsunami inside. Marude questionned Yoshitoki… And many other things.
Overall the bases were already there but once again you need something stronger to shake people and worlds. But he problem remains among Ghouls: will they accept to treat Humans as mere flesh? WIll they stop hating the Investigators when they were all manipulated?