When he first talks to Tsukiyama about books, Tsukiyama makes a comment that the closer the person’s state of mind is to the author, the more the person will enjoy the book.
When Kaneki is withdrawn and upset after attacking Banjou, he tries to read a lot of different stories, but doesn’t enjoy anything he reads until all that’s left is Takatsuki’s new work, The Hanged Man’s MacGuffin. And he muses about how The Black Goat’s Egg started his ghoul life before he starts reading.
Up until this point, Kaneki’s story has paralleled Eto’s – from losing one parent and connecting to them through books, to feeling abandoned by the other parent, to living a hard and violent life as a half ghoul, to becoming a kakuja, to recognizing the wrong in the world. It’s no surprise his state of mind is similar to hers.
But then his story changes. He continues down the same path as Eto, but he’s stopped from losing himself and his humanity completely by meeting Hide in V14 – his human home. Something Eto never had.
That was where Kaneki was when he lost his memories – connected to his human side. The compassionate side that Eto lost as she gained strength to survive.
Sasaki is Kaneki reclaiming his human side. He’s caring and compassionate, towards humans and ghouls alike. He values all life – he doesn’t let the Quinx kill a low level ghoul, and he tells them to run and protect their lives if they can’t defeat an enemy, because their lives are most important.
