帝都物語
Seishiro, with twin characters Subaru and Hokuto, were created by series creator Nanase Ohkawa for a "dōjinshi" novel about an onmyōji who hunts elves. The characters were twice drawn for covers; these characters were used when "South" magazine asked Clamp to create a new series for them. In the dōjinshi, Seishiro was a veterinarian but his dark side was much less pronounced. Seishiro underwent more changes from this early design to the creation of "Tokyo Babylon". Seishiro was easier to write than Subaru by Ohkawa as she has more skill with coldhearted characters like Seishiro's true persona than the kind Subaru. In the "dōjinshi", Seishiro had a conjure being accompanying him (shikigami) which was named "Nandaro" ("Just what is this?"). Clamp privately referred to it by this name during the publication of the series despite it not being mentioned in the manga. According to Yasunori Kato, Subaru and Seishiro's respective designs pay homage to this character and the protagonist of the fantasy novel "Teito Monogatari", who is widely credited with starting the "onmyoji boom" in Japan. The early chapters involving Subaru's meeting with Seishiro set the events of the series' future. Since his introduction, Seishiro has been written with the idea of having an agendum that contrasts with his actions and dialogue with the other characters. When designing Seishiro, Clamp wanted a strong contrast between his facade as a caring man and his cruel persona whenever he is wearing glasses.