Ohba created the characters as "stock villains intended to make the main characters look good." Ohba said that he had always planned for Light to regain his status as Kira, so the specifics of a certain member of the Yotsuba group being Kira would not matter to the plot; Ohba wanted the readers to guess which of the characters was Kira. After seeing Obata's designs Ohba selected Higuchi as Kira. Ohba said that he wanted for Mido to appear to be "the most suspicious" of the Yotsuba group. Ohba added that he created the profiles of the characters while eating dinner with the editor. He believes that he did not "put much thought" into the character profiles. He said that he included a lot of information to serve as red herrings.