Yo-kai Watch Shadowside: Oni-ō no Fukkatsu

Yo-kai Watch Shadowside Oni-o no Fukkatsu is a 2017 supernatural anime film produced by OLM, Inc. and distributed by Toho. It is the fourth film in the Yo-kai Watch film series, following the 2016 film Yo-kai Watch: Soratobu Kujira to Double no Sekai no Daibōken da Nyan!, and features characters from Shigeru Mizuki's GeGeGe no Kitarō manga. It is directed by Shinji Ushiro and written by Yoichi Kato, with Level-5 president Akihiro Hino overseeing the production and script. It was released on Japanese theaters on December 16, 2017 and on DVD on July 4, 2018.

The movie takes place 30 years after the events of the original anime. The original series's main protagonist Keita Amano (known as Nathan "Nate" Adams in English) was a wielder of the Yo-kai Watch, and through it he befriended Yo-kai and fulfilled many great deeds. But as he grew up and married Fumika Kodama (his childhood friend and crush in the first series, also known as Katie Forester in English), he lost his ability to see Yo-kai. The Yo-kai Watch's existence threatened to disturb the balance between the human world and the Yo-kai World, so it was cast away into oblivion beyond time and space. Soon, the story of the Yo-kai Watch became but a legend. But then, many years later, a comet heralds the arrival of a new threat. An epidemic Yo-kai virus known as Onimaro begins spreading and infecting people with malevolent intentions, turning them into Kaodeka Oni and causing chaos throughout the city. With the end near, only the ones chosen by a new Yo-kai Watch can save both Yo-kai and humans from certain destruction and rekindle the bonds between them.