Kunihiko Yuyama, the director of the film, said, "There is an image and setting of an omniscient and omnipotent being who created the world," and there is an episode in which he struggled with the scale of this image when introducing it into the story.
As part of his efforts to express this image, he chose Akihiro Miwa as the voice actor, which had a tremendous impact, and his excellent performance, coupled with the release of the film, led to the widespread use of the term "Akihiro Miwa" or "Miwaseus" as a description of Arceus.
According to director Yuyama, Arceus was too powerful for the scenario to work in its original setting, so he decided to create drama by making it incomplete with missing plates, and to make it more convincing by including a time-slip sequence to solve the problem. The director said that the original setting was too strong for the scenario to work, so he created drama by making the plates incomplete and missing.