M04

is the fourth theatrical film in the Yo-kai Watch franchise. The movie made its debut in Japan on December 16, 2017. It is the first film in the series to be a sequel to the original anime series, as well as the first crossover film with Shigeru Mizuki's GeGeGe no Kitarō franchise.

Blurb
"There used to be a boy who could control Yo-kai with a mysterious watch. However, he became unable to see Yo-kai when he became an adult. With the boy's duties finished, the watch was buried away in space-time. Then 30 years later, quiet everyday life comes to an end as a fateful day beging with a comet drawing near. The terrible Yo-kai virus Onimaro infects people's malevolent intentions and spreads infinitely. The one chosen by the Yo-kai Watch is the one who can save humanity from its crisis. The bond between humans and Yo-kai may be recovered with the attainment of a new Yo-kai Watch."

Debuting Human Characters

 * Natsume Amano
 * Touma Tsukinami
 * Akinori Arihoshi
 * Mitsue Arihoshi
 * Saki Machida (Minor)
 * Keisuke Amano (Cameo)

Debuting Yo-kai

 * Onimaro Leader
 * Kaodeka Oni
 * Jaou Kaira
 * Uura
 * Oniou Rasen
 * Ogu
 * Togu
 * Mogu
 * Fudou Myouou
 * Kitaro
 * Medama-Oyaji
 * Neko-Musume
 * Nezumi Otoko
 * Konaki Jijii
 * Sunakake Babaa
 * Ittan-momen
 * Kitaronyan
 * Thurston (Shadowside)
 * Douketsu

Recurring Humans

 * Nathan Adams (End credits Cameo)
 * Katie Adams (Cameo)

Recurring Yo-kai

 * Whisper (Shadowside)
 * Jibanyan (Shadowside)
 * Komasan (Shadowside)
 * Lord Enma (Shadowside)
 * Zazel (Shadowside)
 * Kyubi (Shadowside)
 * Blizzaria (Shadowside)
 * Hungramps (Shadowside)
 * Blazion (Shadowside)
 * Papa Bolt (Shadowside)
 * Micchy
 * Azure Dragon (Shadowside)
 * Gutsy Bones (Shadowside)
 * Komajiro (End credits Image)
 * Noway (End credits Image)
 * Dame Dedtime (End credits Image)
 * Usapyon (End credits Image)
 * Dai-Yoma Nura-Neira (End credits Image)
 * Narwail (End credits Image)

Pre-release information
The movie was first revealed by the staff behind Yo-kai Watch the Movie: The Great Adventure of the Flying Whale &amp; the Double World, Nyan!. They've stated that the fourth movie would be released during the winter of 2017 and that they would reveal its release date and its title on a later date.

In July, 2017, the title and its release date was revealed in which features Lightside and Shadowside transformations of various Yo-kai. It is revealed that they would have the ability to transform into "lightside" and "shadowside" forms. In these forms, Yo-kai show different personalities, abilities, and appearances. The magazine shows pictures of Jibanyan, Komasan, and Whisper in lightside and shadowside forms. Akihiro Hino also described the film as a "completely new horror comedy", and would be much darker in tone than the previous films.

The plotline of the story focuses on three new human characters. The first is Natsume Amano, a 13-year-old Junior High School girl and also the daughter of Nathan Adams, who nearly drowned in a river when she was very young. She remembers "something" saving her from drowning. Second is Touma Tsukinami, a 13-year-old Junior High School boy whose parents are busy with work, so he is always alone and is mysteriously attracts Yo-kai. The last is Akinori Arihoshi, a Shaman-in-training and the oldest of the Arihoshi Siblings, whose family uses Yo-kai in fortune-telling for generations.

Later in September 13, Level-5 officially announced the film to be a crossover with Shigeru Mizuki's GeGeGe no Kitarō manga series, and with the titular characters appearing in the film. The film's second trailer was later released in October of 2017.

Casting
Most of the cast from GeGeGe no Kitaro returned to reprise their roles in the film as well as some newcomers. will reprised her role again as Kitaro, 9 years after last voicing her character in the 2008 Anime Adaptation of the original Hakaba no Kitarō manga. Other cast that appeared in the film are voicing Touma and  voicing Natsume while  and  voiced Jibanyan and Komasan respectively.

Video gallery
「映画 妖怪ウォッチ シャドウサイド 鬼王の復活」特報|Yo-kai Watch Shadowside: The Return of the Oni King teaser. 「映画 妖怪ウォッチ シャドウサイド 鬼王の復活」予告||Yo-kai Watch Shadowside: The Return of the Oni King trailer. 「映画 妖怪ウォッチ シャドウサイド 鬼王の復活」シャドウサイド予告|Yo-kai Watch Shadowside: The Return of the Oni King Trailer 2.

Trivia

 * This is the first Yo-kai Watch film to be a sequel to the original anime series, and thus it also functions as the pilot of the Shadowside anime series.
 * The film itself marks as the first where and  do not voice Jibanyan and Komasan receptively.
 * This is the first film where Hovernyan doesn't make an appearance.