Rubén Arnaiz was inspired by his love of the Marvel horror comics of the 70s (Tomb of Dracula, Man-Thing, Werewolf by Night, and Monster of Frankenstein) to write the story, in addition to the work of H.P. Lovecraft and Clive Barker (especially Hellraiser) and Kelley Jones's The Hammer published by Dark Horse Comics.
Filming was supposed to begin in the summer of 2021, but Rubén Arnaiz was called up for the film Scavenger in Mexico. After returning to Spain, he decided to write a completely different script for the film.
Unlike what usually happens, the screenwriter did not rewrite the script several times but wrote three completely different scripts, only keeping the main plot, until he found the right story.