Shuichi Aizawa

Shuichi Aizawa (相沢 周市, Aizawa Shūichi) is a member of the Kira investigation team that leaves the team under the guise of needing to support his family because the Japanese police cut their funding, though L would have paid for it. He leave the force because of L's is curious about him and make him annoyed with L's attitude. He returns after L's death, where he is one of the first to suspect Light of being Kira, and helps contribute to his eventual defeat. He becomes the leader of the investigation team afterwards. He is voiced by Keiji Fujiwara in the Japanese anime and Trevor Devall in the English dub. In the film, he is played by Tatsuhito Okuda.

Aizawa has a wife and child, named Eriko and Yumi. Aizawa and his wife also have a baby son. Halfway through the series, it is implied that Aizawa and his wife were having marital problems, as a result of his (Aizawa's) working on-call 24 hours and rarely being home. Aizawa's daughter and wife both seem to miss him, and Yumi is happy whenever he comes home. However, his wife Eriko tends to take it in a more hostile manner; When the NPA discontinues to provide support for the Kira Investigation Team, Aizawa is forced to quit and return to the NPA in order to provide income for his family. He is shown in a park, where by chance he sees his family; he begins to cry while holding his daughter. Even though he is most obviously troubled, his wife only replies, "You need to call me when you're going to show up for dinner. I only bought enough food for Yumi and I." It is unknown in both the manga or anime whether he and his family were able to mend, as they are not mentioned by Aizawa after the incident.

Obata said that he did not plan to draw Aizawa for an extended period of time, so he "began to worry" when Aizawa continued appearing "more and more." Obata felt that originally his face was not "good for a main character" so he said he decided to "gradually make him more presentable. [laughs]" and increase the volume of his hair. Obata believes that Aizawa was "easy to draw" and that it is easy for him to draw people who "act consistently." Obata said that he drew Aizawa while believing that "it would be nice if there were lots of people like him in Japan." Obata redesigned Aizawa to "look older" and "really make it feel like four years had passed since L's death."

Towards the end of Death Note, Ohba decided to make Aizawa the chief of the NPA because he did not want to create a new character in the final chapter. Ohba felt that Aizawa is the best person to be the NPA head because Aizawa held connections to the Japanese police and knows Near. Ohba also said that whilst the other former Kira Investigation Team members had the same qualifications, he did not want to use Mogi due to his lack of personality development, nor Ide because he was so recently re-introduced and readers knew so little about him. Then he laughingly added, "Matsuda was out of the question! Maybe after Aizawa retires? We will see if he matures..." Obata then asked Ohba: "Do we make a new manga for just Matsuda?" And Ohba replied, "Of course not. Baka [Idiot] Takeshi-san." [Note: Ohba was joking with Obata, making a refference to the phrase often used by L, Light, and Aizawa: "Baka Matsuda!" [In english dub, "Matsuda, you idiot!"]