People like Eiji Otsuka

MPD Psycho, short for Multiple Personality Detective Psycho (Japanese: 多重人格探偵サイコ, Hepburn: Tajū-Jinkaku Tantei Saiko), is a manga series written by Eiji Ōtsuka and illustrated by Shou Tajima, published by Kadokawa Shoten from 1997 to 2016. The series follows a police detective suffering from multiple personality disorder.

MPD Psycho was adapted as a live action television miniseries in 2000, directed by Takashi Miike.

Yôsuke Kobayashi is a detective and is on the case of a serial killer who dismembers his victims. The killer later sends Yôsuke's girlfriend dismembered but kept alive. Yôsuke hunts down the killer and due to the events, loses his sanity and develops Dissociative identity disorder with the two main personalities being Kazuhiko Amamiya, a cool headed detective and Shinji Nishizono, a reckless psychopath. After being placed in prison for murdering the killer, Yôsuke Kobayashi is released and works for an independent detective agency ran by Machi Isono. Later serial killers are appearing with barcodes in their left eyes, which Yôsuke Kobayashi also has. Yôsuke Kobayashi investigations lead him to believe he is not who he thinks he is and that his Kazuhiko and Shinji personalities have existed since childhood.