Swiss artist H. R. Giger, best known for his work on Ridley Scott's ALIEN, contributed concept art for the film. He originally showed interest in working on set, however his schedule would not permit it.
The film's production was plagued by several accidents. Some people believed this was the real life spirit of Taira no Masakado (still considered a revered deity in Tokyo) causing trouble for the staff, while others accepted the reality that accidents happen on film sets all the time, and there is no such thing as a curse.
In 1988, this was arguably the most expensive Japanese fantasy film of all time boasting a budget of around $14 million (when converted from yen).
The character of Dr. Makoto Nishimura is based on the historical biologist and inventor of the same name. He is played by the historical scientist's real life son, actor Ko Nishimura.
The scene where Koda Rohan cuts off Kato's hand is a direct reference to the myth of Watanabe no Tsuna and his encounter with the demon Ibaraki at Modoribashi Bridge. In the original legend, Tsuna chops off the demon's arm before it flies away. The film makes this explicit at the beginning: When Koda is first shown in the film, he's looking at a tapestry of Watanabe no Tsuna with his sword drawn chasing a demon flying away into air. This foreshadows Koda's encounter with Kato.