text: Animation Character designer Yūji Iwahara inspired Okamura to work on Darker than Black, based on his work on the video game Koudelka and its manga version. The narrative was inspired by Japanese dramas which divide stories into two consecutive episodes. As a result, every story of Darker than Black takes two episodes to finish. Okamura wanted to give his audience comic and dark stories for variety. Actual locations, including Shinjuku and a police station, were photographed to make the series more realistic. According to Iwahara, Hei was the most difficult character to draw; he struggled for a subtle balance when designing the character. Hei's black eyes were smaller, creating a cold impression, later becoming more expressive. Li, his civilian persona, was originally gentle-looking. Iwahara accepted the offer because he was interested in the project, and wanted to do something different after his previous serialized manga. Although he found the character sheets easy to do, he was daunted by the number of characters he had to create.
  The team was tasked with depicting super-powered individuals fighting against a Tokyo backdrop, which was complicated. Okamura found early designs unacceptable; until his image of the characters matched Iwahara's, the pictures were redrawn many times. Iwahara found his work on the anime more challenging than his manga, since he had to keep up with staff requests and had little artistic freedom. Takahiro Komori adapted Iwahara's work for animation, retaining the essence of the original designs and making the animators' work easier; Huang's hat and Yutaka Kouno's and Mayu Ootsuka's clothing were changed. Colour designer Nobuko Mizuta was disappointed because much of the series is set at night and the main characters' clothing is generally dark-coloured, but she gave the guest characters brightly-coloured clothes. Komori said that when he draws female characters, he pays special attention to the line connecting her buttocks and legs. The series' first opening scene has a silhouetted nude woman following Hei, which had to be corrected in subsequent episodes. The artist had mixed emotions about sexualizing female characters but in the end decided to sexualize them to appeal to the audience.