In anime, filler episodes are conceived for a multitude of reasons. Sometimes, they are meant to pad out a season with extra content that is not part of the manga the series is based on. Other times, if the anime production catches up to the publication schedule of the manga, fillers function as a means to give time to manga creators to put out more content to adapt.
Typically, fillers are only a few episodes, and in modern times, anime studios do not resort to producing these. The latest outlier is the recently concluded fourth season of the extremely popular “Demon Slayer: Kimetsu no Yaiba,” where seven out of its eight episodes are filler.
Adapted from Koyoharu Gotouge’s manga’s very short story arc, a majority of the episodes from the “Hashira Training Arc” season are quite inconsequential.
A brief respite
After the climactic battle in the last season led to Nezuko Kamado gaining the ability to withstand sunlight, Kagaya Ubuyashiki realizes that series villain Muzan Kibutsuji will seek to capture her to gain her ability. If the demon lord overcomes his species’ weakness, the complete subjugation of Japan will be swift.
Placing Kamado under the protection of the Demon Slayer Corps, Ubuyashiki enacts the Hashira Training regiment for the entire Corps members to strengthen them for the eventual battle against Kibutsuji and his demons.
The straightforward premise serves as the basis for the seven episodes in the season, where the most promising Corps members, such as lead characters Tanjiro Kamado, Zenitsu Agatsuma, Inosuke Hashibira, and Genya Shinazugawa, undergo training by the eight Hashira-ranked Demon Slayers.
Instead of the high-octane fights and brutality from previous seasons, the episodes are much more lighthearted, featuring comedy and banter with the cutesy animation of exaggerated shouting and bulging eyes that Gotouge’s manga is known for.
The episodes are fun and expand on character dynamics somewhat, but by the fourth episode, the hunger pang for something meatier than non-stop jokes and for the story to pop off quickly becomes overpowering.
Setting up the finale
Viewers who choose to skip the first seven episodes will not miss a single thing, as the story does not develop in any meaningful capacity. It is the final episode that is the most important in the entire season, and animation studio Ufotable knows it.
After successfully locating the bedridden, almost dead Ubuyashiki, Kibutsuji confronts him, hoping that by killing the leader of the Demon Slayer Corps, the organization will give up fighting against the demons.
Ubuyashiki then pulls an Uno reverse card, and Ufotable dumps the entire season’s production budget into this single episode, blending high-quality CGI and animation to deliver a great but somewhat short action set piece.
As the Hashiras and Tanjiro converge on the location of Kibutsuji, who has been trapped by Ubuyashiki’s plan, the Michael Jackson-looking demon pulls his Uno reverse card, teleporting the Hashiras, Tanjiro, Zenitsu, Inosuke, Genya, and the entire Corps into his demon-infested hideout and lair: Infinity Castle.
Some of the best highlights from the episode are Stone Hashira and Gyomei Himejima finally revealing his weapon, an axe attached to a flail similar to the Japanese “kusarigama.” Viewers are also exposed to Muzan’s rapid healing for the first time after he regenerates 90% of his body that exploded, and how his entire head regenerates after Gyomei smashes it.
The stage is now set for the final “Demon Slayers” arc, except there will be no fifth season. The series “Infinity Castle Arc” will be told in three feature-length films. As each season has followed a strict one-season-a-year schedule, the first film is expected to be released late next year.
“Demon Slayer: Hashira Training Arc” is streaming in full on Netflix.
