Whether it is Naruto, which has even more, filler has a bad reputation most of the time in anime. Simply put, fillers are episodes original to an anime, often included to pad runtime or stretch a season out. There can be a few reasons for this. Sometimes, the manga will still be in development, so to buy time, an anime can produce original ideas to give the source time to catch up. Other times, filler can be used to develop characters more or give a series a breather in between heavy arcs.

While it is seen as excessive and unwanted by some, there have been Spy X Family by Tatsuya Endo. While the anime does faithfully adapt the manga, a lot of the episodes could come off as filler based on their tone and how disconnected from the main plot they are. However, these are canon chapters in the manga, but they are done in this style because these episodes can be just as fulfilling and fun.

Just Because It Is Not Plot-Related, Doesn't Make It Filler

Spy X Family's Plot Takes A Backseat To The Family's Relationships And Humor

To be clear, Spy X Family does not have a lot of filler episodes in a traditional sense. For the most part, it's been adapting the manga faithfully. With that in mind though, a lot of the episodes and chapters deviate from Spy X Family's overarching plot. Agent Twilight needs to get access to an illusive political figure, and to do so, he puts together a fake family to infiltrate his target's inner circle, specifically relying on his adopted daughter, Anya, to befriend his mark's son, Damian.

While "Project Friendship" is often on Anya's mind, and Agent Twilight sees almost every move they make as a means to achieving his goal, there are a lot of moments in the manga and anime of the family just growing closer, like when Agent Twilight, AKA Loid Forger, takes his "wife" Yor Briar on a string of dates to maintain appearances. Meanwhile, there are some funny Spy X Family moments that are played for laughs more than they are the plot, like Yor's tennis match with Loid's partner from work, Fiona Frost. Similarly, there are even action sequences that don't seem to benefit the direct plot, but they are some of the best, like when the dog, Bond, and Loid save a puppy from a burning building.

If it just stuck to the direct plot of Twilight trying to infiltrate the Desmond family, it would not be as interesting.

All of these scenes and episodes work so well for Spy X Family because they develop the relationships and characters so much. Moments like these also keep the mood light and humorous, one of the biggest selling points of Spy X Family. This is a hilarious anime with tons of heart, and if it just stuck to the direct plot of Twilight trying to infiltrate the Desmond family, it would not be as interesting, even when the espionage elements of the series are top-notch on their own.

Spy X Family Sometimes Pads Its Anime For The Better

When Adapting Spy X Family, The Action Sequences Are Better Extended

Where the tone and side quests of Spy X Family can come off as filler, even when they are pulled from the manga, that is not to say the anime isn't guilty of padding out runtime. Though Spy X Family's filler is still at the same level as its source material and at times, it even elevates said material, especially when it comes to the action. Perhaps the best example of the anime expanding an action sequence is when Loid brings Anya's favorite show, Spy Wars, to life.

Not only is this one of Loid's best moments from Spy X Family, but it also shows how the anime can go beyond what's from the manga. The action from the manga is turned up to an eleven in this sequence, showing off how Loid and Yor are forces to be reckoned with. By expanding this sequence, it also allows for more humor. This sequence captures what makes the anime a must-watch, and it is an expansion of its source material -- filler.

Can Filler Work For Other Shōnen Anime?

Demon Slayer Shows That Filler Works For More Traditional Shōnen Series Too

Spy X Family's "filler" works, but that has a lot to do with what the manga is setting out to do. Yes, the general plot is about Agent Twilight using this fake family to get access to an elusive political figure; however, the heart of the series is the family itself. As a result, it works to have most of the series dedicated to episodes that could come off as slice-of-life. However, filler can still benefit other shōnen series.

Take for instance Demon Slayer, which is a shorter shōnen than most. Due to its length, the anime needs to pad out some of the fight sequences, but it does so in a way that elevates the anime above the manga. While other anime pad their fight sequences through reaction shots, Demon Slayer instead focuses on animating the fights to be unlike any other. The animation is not just gorgeous, but it also raises the stakes as these fights truly feel larger than life.

Meanwhile, the most recent season of Demon Slayer adapts one of the series' shortest arcs. It's a training arc, as well as the calm before the storm. This finale is set to be a nightmare for the Demon Slayer Corps, so a moment to breathe is absolutely necessary for the series and fans. It's also the season that is tasked with giving some characters more development, especially since some Hashira -- like the Wind, Stone, and Snake Hashira -- have not had their defining moments in the series yet.

To best adapt this arc, stretching chapters out is necessary. If anything, it gave the arc enough material to be a season, and it made the climactic finale of the season all the more shocking. Demon Slayer is not alone in proving filler can work, with the latest One Piece special, One Piece Fan Letter, being one of the anime's greatest releases, and it is nothing but filler. It also focuses on the heart and characters of One Piece over the main plot, which is exactly what Spy X Family does in the manga and in its anime adaptation.