After his defeat at the hands of Kishou Arima during the Owl Extermination Operation, CCG incorporated Ken Kaneki as a ghoul investigator.

He went by a new identity Haise Sasaki, a half-ghoul under the tutelage of Arima and Akira Mado (mentor). During this phase, he was quite loyal and dedicated.

He wanted to protect humanity and also the CCG. But, Kaneki (or Haise Sasaski) was not hellbent on exterminating the ghouls. He showed mercy towards them. 

Kaneki’s underlying personality was still deep-rooted in the ideology of protecting others.

However, the major change in his outwardly appearance and behaviour created a lot of confusion at the beginning of Tokyo Ghoul:re.

In fact, fans still question how Kaneki became the Ghoul Investigator Haise Sasaki. How did his personality change? What did the CCG do to him?

How did Kaneki become Haise Sasaki?

Kaneki became Haise Sasaki after he lost his memories about his past.

Seeing that he had lost his memories, Kishou Arima came up with a new name and identity for Kaneki (Tokyo Ghoul:re chapter 67).

For this purpose, Arima asks Kaneki to choose his two favourite Kanji characters.

Kaneki chooses kanji from the words coffee and world, which makes his name Haise. It is a combination of the second character in the word coffee and the first character in the word world.

In German, the name Haise means “no name”.

During this time, Kaneki was a prisoner at Cochlea. His mental state was also bad due to his defeat at the hands of Arima. 

Once his condition had improved, Arima took him under his wing and trained him to be a ghoul investigator as part of his rehabilitation program in the CCG.

Haise would look up to both his mentors Akira Mado and Arima. He would come to accept them as parental figures in his life.

But the question remains, did Kaneki really forget everything about his past life? Did he lose his memories?

Well, losing memories was the key to Kaneki transforming into Haise. So, lets take a look at what happened there.

How did Kaneki lose his memories?

Kaneki lost his memories after his defeat at the hands of Kishou Arima in the Owl Extermination Operation.

Contrary to the popular belief, Kaneki suffered from amnesia not because of the brain damage he received, but because he forcefully suppressed his memories. 

During their fight, Arima inflicted Kaneki with a serious head injury after piercing his Quinque through his eye and subsequently his skull.

Fans saw this as the primary reason for Kaneki’s memory loss.

While this attack disoriented Kaneki, he still had some part of his memory intact. This is hinted in Tokyo Ghoul:re chapter 67.

We see Kaneki fervently asking to be released from his detention ward in Cochlea, so that he could go rescue the others. 

However, Arima pushes him into further despair saying that he killed all of them, which referred to his friends at Anteiku. Knowing that he was unable to save them, Kaneki’s mental state deteriorates further.

He subconsciously suppresses his identity and his memories so that the loss of his close ones won’t cause him any more pain.

He kept on crying and clawing at his eyes, refusing to eat anything.

Seeing that he won’t survive long if he continued to do so, Arima starts bringing him books to read. Eventually, Kaneki calms down (thanks to the books).

Following this, he is given the new identity of Haise Sasaki.

Major stress can cause Amnesia. In Kaneki’s case, a combination of brain damage and heavy stress triggered his memory loss!

Did you hate Arima for what he did to Kaneki? Did you realise Haise Sasaki was Kaneki? Let us know your opinions in the comments section!