Kishou Arima  

During the third Cochlea raid, he begins fighting Sasaki, who has regained his memories. Though Sasaki declared the battle over, Arima charged him and stated the battle will not end until one of them died. He continued to attack with the broken quinque, slashing apart tentacles until he closed the distance between them and stabbed Sasaki through his abdomen. However, Sasaki pleaded with him to accept his defeat, voicing his belief that continuing is meaningless. Arima stepped back, lowering his broken quinque and asked whether Sasaki has no intention of killing him. He revealed himself to be a Half-human, a ghoul-human hybrid born without a kagune and bred by the Sunlit Garden. Because of his hybrid nature, he had developed glaucoma as a result of an accelerated aging progress and would soon die from old age. He revealed to Sasaki that the Washuu Clan are ghouls, and entrusted him with his final wish -- asking Sasaki to take credit for his death. He turned his gaze upwards, musing that in his eighteen years as an Investigator, he has never faced an opponent he could not defeat. Once more, he asked Sasaki whether he will really not finish him off. Sasaki confirmed his decision once more, and after stating his understanding, Arima slashed his own throat with Owl.Mortally wounded, Arima collapsed with blood pouring from his throat and mouth. As Sasaki held him, he used the last of his strength to confess his many secrets. He promised that Sasaki would understand soon enough, and admited that he always hated his own existence as someone that could only kill, taking the lives of others while never giving anything to the world in return. With his dying breath, Arima praised Sasaki as something he could leave behind and lifted his hand to touch his face, before succumbing to his wounds.