A series of consecutive murders targeting only drug syndicate dealers occurs. At the crime scenes, cryptic blood messages are left behind, and from eyewitness testimonies, the culprit is dubbed the "Red Coat Killer." As DEUS progresses with the investigation, a tragedy involving a young couple emerges, hidden within the events.
The episode is, in fact, connected to the canceled 2005 film ULTRAMAN2: requiem. Yuuki Kuroda, who plays Kyosuke Agata in this episode, was originally cast to appear in the film. He was set to portray Toma, a character described as "a friend of the protagonist who becomes reclusive after an earthquake and wishes for the resurrection of a deceased female friend." Later in the film's storyline, Tōma would transform into the antagonist known as "Human Element."[2][3]
Although the casting for ULTRAMAN2: requiem had been finalized, the production of the film was ultimately canceled. When Ultraseven X was being developed, Kazuya Konaka reached out to Kuroda again, which led to his casting as Kyosuke Agata in this episode. Interestingly, there are notable similarities between Toma and Kyosuke Agata—both are characters unable to come to terms with the death of a female friend or romantic partner.
During the production of "Blood Message," Konaka had the intent to incorporate elements of ULTRAMAN2: requiem. Similarly, Keiichi Hasegawa felt that he had actively infused this episode with ideas he had wanted to explore since Yellow Eyes but had not been able to implement previously.
Hasegawa stated that this episode was based on a concept he had previously developed for other works. Since the key theme of the story was "memory," and it fit well with the series' worldview, he adapted the idea to match the Ultraseven X style. Additionally, given that the series aired in a late-night slot, he was able to present it in a deeper and more complex manner than his original idea.
Upon learning that "BLOOD MESSAGE" would be placed in the latter half of the series, lines were added to reinforce the fact that Jin had lost his memory.
In the scene where Asami nonchalantly eats despite blood splattering on her face, the original script had the blood staining her pure white clothing instead. However, upon hearing that Mahiru, who appears in episode 9 "RED MOON," would also be wearing white, Hasegawa suggested changing Asami’s outfit to a red dress while keeping the blood splatter on her face.
The name "Hupnath" was derived from the word "hypnosis," which carries the meaning of inducing sleep or suggestion.
In the theater scene, titles of Alfred Hitchcock's thriller films such as Psycho and Vertigo appeared, and the episode's plot was also influenced by these films.
Hasegawa explained that within the world of this series, such movie titles indeed existed, but this simply suggested the presence of extremely similar films in this universe.
At the story's conclusion, the blood-written "notman" was revealed to be "Norman," a direct reference to the spelling of Norman Bates' name in Psycho.
Hasegawa noted that due to budget constraints, he aimed to make the plot structure more intricate. In self-contained episodes like this, the impact of the final twist significantly influences the audience’s impression, so he placed particular emphasis on the revelation of the culprit’s message. If "norman" had been read correctly from the beginning, it would have essentially spoiled the mystery. Instead, he structured it so that the "r" was initially left unpronounced, leading to a deduction about whether it was actually a "t," allowing the story to unfold as a mystery. However, this approach sparked debate during script discussions.
