It is known that Arima Kishou was the One Eyed King. He had taken the title because even though he was a half-human (physically human but with the abilities/senses of a ghoul, excluding the kagune). … And so it was spread that the one who kills the One Eyed King will be the hope and saviour for all ghouls.
Season 3 (Tokyo Ghoul:re, Season 1)
The character of Haise Sasaki was introduced as a replacement for Ken Kaneki in season 3 of the anime but as it soon turned out, Haise Sasaki was actually Ken Kaneki.
He does not die, when he fought Arima shortly after walking with Hide in his arms, he nearly died since Arima stabbed both of his eyes, going through a part of his brain, but luckily he didn’t die, instead it wiped out his memory almost completely.
Kanae when entering the Tsukiyama household. … As Kanae, he was taken in by the Tsukiyama family, an act seen by other servants as charity. During this time, he began to serve Shuu Tsukiyama and would become extremely loyal to him and eventually developed romantic feelings for him.
Who is Sasaki Haise? – Quora. He is the same person as ‘Ken Kaneki’. It’s just that after his defeat to Kishou Arima during the Owl Extermination, he had Amnesia. He was then brought up as a ‘Ghoul Investigator’, and trained under Arima.
Based on the trailer and other teasers, Haise will go through the transition into being Kaneki again at the beginning of Tokyo Ghoul season 4. However, many fans have varying predictions on how the final season will conclude.
Kaneki turn into a Kakuja because of repeated cannibalism (higher ghoul to human ratio). It is said that through cannibalism, a ghoul absorbs RC cells, and this increases the concentration of RC cells within a ghoul’s body. A Kakuja can form through continuous acts of cannibalism or extreme levels of stress and trauma.
Kaneki’s time at the CCG as Haise gave him practice and training under Arima – the white reaper of CCG. That made him better with sword art and earned him the name ‘black reaper’. His emotional side is what gives him the most strength. That side of him gave him strength to kill Yamori and take on Arima.
Tokyo Ghoul:re is the continuation of Tokyo Ghoul. If we follow the original age of Kaneki (in the first chapter of the manga it labels him as 18, but somehow we all decided that he was 20 at the end of the manga), then it should have picked up 3 years later, seeing as he is 21 or 22.
The main reason as to why Kaneki is so strong is because he is a half ghoul and not a full ghoul. It is mentioned that half ghouls are more powerful than normal ghouls. This can be proven as Ken and Eto (or the One-Eyed Owl) are the two most powerful ghouls in the anime and both of them are half ghouls.
