Creation and conception
toi8 of Studio 4°C was initially asked to work on the series' character designs, but the job was passed on to his wife, Tomomi Ozaki, due to time constraints. According to Ozaki, director Kazuhiro Furuhashi requested that the characters "should not look like manga characters or too real; and not too anime-like," and that he wanted the designs to be faithful to historical details. Ozaki sometimes referred to historical portraits from the series' time period as reference for her designs, as well as actors in Western films, mentioning that she referred to Brigitte Bardot's hairstyles while designing Anna Rochefort's hairstyles, and used Brad Pitt as the reference for Durand.[9]
Writing
When we work on a series, we often scrape off unwanted aspects of each character as the series progress and the characters develop because we gradually realize the main qualities of each of them. For Le Chevalier D'Eon, I think we almost never removed any content from the main characters' resumes that was set at the start. I feel we were able to keep the intended atmosphere of a cathartic drama of people who were and were not loyal to their country 'on the eve of the French Revolution.' We stayed true to the plot given to us initially and I feel we actually added depth to it. Scriptwriter Shotaro Suga was contacted by Tetsuya Nakatake at the beginning of the project, and agreed to work with them when he was informed that Tow Ubukata and Kazuhiro Furuhashi were taking part in the production. He was unable to work on the project immediately, as he was also working on Eureka Seven at the time. Suga admitted to being nervous about working with Furuhashi, whom he described as an "experienced director" because the other series he worked on (such as Ghost in the Shell: Stand Alone Complex, Blood+, Eureka Seven, and Casshern) were by first-time directors. He described the script readings for Le Chevalier D'Eon as "ever more intense" than his previous projects, and that they all "kept on debating to scrutinize each and every detail." Chief writer Yasuyuki Muto noted that their script meetings lasted as long as twelve hours.[10]
Muto was in charge of the script for eleven out of the twenty-four episodes.[10] Ubukata and Furuhashi provided the ideas for the episodes, which the writing staff then adapted into the scripts. "Director Furuhashi as well as Ubukata-san, who is a novelist, both put a lot of weight on the dialogues", Muto said. Suga commented that "[c]ompared to other works, the script for Le Chevalier D'Eon is enormous", noting that one episode had a one hundred-page script.[11] Muto noted that their main focus while writing was the "...'emotion' of each character". Muto was present during the productions' post-recording sessions, primarily because he believed that it would be easier for the staff to have a writer on-hand in case problems arose during recordings.[10]
According to Furuhashi, the script for the series took about roughly ten months to complete, and that thanks to their collaboration with a novelist (Ubukata), the script contained 30 to 40 percent more information than a regular television script.[12]
Design and animation
Art director Hiroshi Ono stated that he initially could not make up his mind whether to work on this project or not, saying "The information they gave me was enough to see that this was not going to be a straightforward job. The story takes place in Versailles and stretches from France to Russia and England. This means that you can't reuse the same background elements throughout the series, and instead you have to create new ones for each episode. Traveling stories are always the most difficult projects of all." Ono was responsible for the background designs used in the series, and he used photographs and classical paintings as references.[13] 3D CGI was used in the creation of certain backgrounds and settings for the series, such as the Hall of Mirrors.[14]
toi8 of Studio 4°C took on the role of designing the weapons and props for the series. He utilized different reference materials for his designs, saying that he "relied on images in books and on the web" as well as films such as Fanfan la Tulipe and The Affair of the Necklace.[15] toi8 was initially asked to work on the series' character designs, but the job was passed on to Tomomi Ozaki due to time constraints.
Music
Composer Michiru Oshima stated that this is "the first time in years" that she was given the chance to compose pieces that were "very classical". She stated that while she was composing the music for the series, she was "consciously trying to add depth that's typical of European classical music", and that she believed that orchestral pieces suited the series well because the characters "are all serious and weighty."[17]
The song "BORN", composed and performed by Miwako Okuda, is used as the series' opening theme for all twenty-four episodes. The series' ending theme ("OVER NIGHT" by Aya), which is also used for all twenty-four episodes, was specially composed for the project. Aya stated that she drew inspiration from the first illustration she was shown, which was of "D'Eon, splattered with the blood of his victim, [walking] in the burning city of Paris holding Lia's hands."[18]
