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.

Plot
The movie takes place 30 years after the events of the anime. The original series' 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 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.

New characters

 * Mone Kamishiraishi as Natsume Amano (天野ナツメ). She is Nate's daughter, who nearly drowned in a river when she was young, but survived after someone saved her. She is chosen by the new Yo-kai Watch, the Yo-kai Watch Arcane, allowing her to harness the power of summoning Yo-kai to protect both Yo-kai and humans from the Demon King.
 * Yudai Chiba as Touma Tsukinami (月浪トウマ). He is a junior high schooler who has become isolated since his parents are away overseas. Due to this, he is often bullied and harbors hatred towards people, never wanting to mingle with them. He is cursed by one of Rasen's followers and becomes an agent of the Onimaro, wielding the Kigan Gear to spread evil and malice. Later in the film, the Kigan Gear transforms into the Yo-kai Watch Ogre, allowing him to transform and fight against the Onimaro and the Demon King.
 * Mutsumi Tamura as Akinori Arihoshi (有星アキノリ). He is a shaman in training and the oldest of the Arihoshi family, who has used Yo-kai in their fortune telling for many generations. He is capable of using magic and uses spells and incantations to take down Yo-kai.
 * Masako Nozawa as Kitaro (鬼太郎), a Yo-kai kid who is the last remaining member of the Ghost Tribe. He lives with his father, Medama-Oyaji (目玉おやじ) (voiced by Bin Shimada) and looks after humans while acting as a mediator between them and Yo-kai. He becomes involved with the Onimaro invasion and the arrival of the Demon King, assisting Natsume and Touma in stopping him.
 * Akio Ōtsuka as Nezumi Otoko (ねずみ男), a rodent-like human and Yo-kai hybrid and Kitaro's friend, though he sometimes backstabs him and his friends through his vile schemes.
 * Yuko Minaguchi as Neko-Musume (ねこ娘), a human-like Yo-kai who is close friends with Kitaro and transforms into a monstrous catgirl when angry. She harbors a slight crush on Kitaro and despises Nezumi Otoko.
 * Other members of the Kitarō Family except for Nurikabe (ぬりかべ); Konaki-Jijii (子泣きじじい) (voiced by Kōzō Shioya), Sunakake-Babaa (砂かけばばあ) (voiced by Hiroko Emori), and Ittan-Momen (一反もめん).
 * Jun Fukuyama as Lord Ananta (蛇王カイラ), a humanoid Yo-kai and a longtime rival of Lord Enma, who wishes to become the new king of the Yo-kai World. He initially has an antagonistic role, but comes to help the protagonists fight Rasen.
 * Unshō Ishizuka as Demon King Rasen (鬼王・羅仙), a powerful Yo-kai who feeds upon human "malice" and can harness humans and Yo-kai's "inner darkness" to control them. He was sealed away several years ago before being resurrected in the present and starting an invasion on Earth.

Production
First announced on the screening of Yo-kai Watch: Soratobu Kujira to Double no Sekai no Daibōken da Nyan! greeting event on December 4, 2016. The film was first revealed in the July Issue of Shogakukan's CoroCoro Comic magazine, which also revealed the new Lightside and Shadowside forms of the Yo-kai featured in the film. The film's official plot and characters were revealed in the official movie website alongside the staff working on the movie. Akihiro Hino stated the movie is a "completely new horror comedy" that would be scarier in tone compared to the previous films, but still have humor. As well, the new characters would have darker backstories and Yo-kai would have Lightside and Shadowside forms. Level-5 later announced in September that the film would be a crossover with the manga series GeGeGe no Kitarō, with veteran voice actor Masako Nozawa reprising her role as Kitaro.

In later announcements for the film, the voice actors for the two main characters were revealed, with Yudai Chiba voicing Touma and Mone Kamishiraishi voicing Natsume. In October 27, the main movie website was updated, revealing more voice actors who would reprise their roles in the film. However, Takaya Kuroda and Daisuke Hirakawa were revealed to be the new voices of Jibanyan and Komasan, replacing Etsuko Kozakura and Aya Endō respectively. The voice actors for Medama-Oyaji, Neko-Musume and Nezumi Otoko were also revealed, and a second promotional video was released.

Music
Series composer Kenichirō Saigō wrote the film's score for its original release. The film's ending themes are titled Yuki no Hi no Saikai (雪の日の再会) by Kota Okamoto and Yōkai Taisō Dai-ichi GeGeGe no Kitaro ver. (ようかい体操第一 ゲゲゲの鬼太郎Ver.) by King Cream Soda.

Release
The film was released in Japan on December 16, 2017 and on DVD on July 4, 2018. Early pre-orders of movie tickets allowed viewers to obtain an Lord Acala Amulet Card, which can be scanned through the Nintendo 3DS to obtain the character in Yokai Watch Busters 2.

Reception
The film earned 399 million yen in its first week, debuting 2nd in the Japanese box office behind Star Wars: The Last Jedi. It stayed in the 2nd spot within the 2nd and 3rd week, before falling to 5th place. Within the span of 8 weeks, it earned more than ¥1,863,413,400.

Sequel
Though no new films were announced in the film's post-credits scene, it is followed by the anime series Yo-kai Watch Shadowside, which premiered on April 13, 2018. Yo-kai Watch: Forever Friends, a film serving as a prequel to the original anime series, was released in Japanese theaters on December 14, 2018.