Clive Barker, the novelist behind The Hellbound Heart and Books of Blood, revealed that he is planning "a number of anime projects" in collaboration with director Ryuhei Kitamura (Azumi, Versus) in an interview with Cinema is Dope. Barker explained that he hopes to see his 1984 short story In the Hills, the Cities animated since it "could not conceivably be made as a live-action movie." According to Barker, Kitamura suggested that the story could be adapted to anime instead.

Kitamura previously directed the 2008 live-action film adaptation of Barker's short story, The Midnight Meat Train. Barker praised the film and decried the release difficulties it encountered around the world.