Toriyama Sekien
The film focuses largely on creatures from Japanese mythology known as "yōkai" (妖怪, variously translated as "apparition", "goblin", "ghoul", "spirit", or "monster"), which came to prominence during the Edo period with the works of Toriyama Sekien. It also draws inspiration from Aramata Hiroshi's "Teito Monogatari", with the novel's antagonist Katō Yasunori appearing as the main antagonist in the film.