Many anime franchises, particularly shonen battle anime, have an incredible amount of filler -- so much so that if one were to watch those shows non-stop from start to finish, it would still take weeks to get through them. There are several reasons why series incorporate filler episodes that introduce scenes that never happened in the original manga. Sometimes, so much filler is included that more than half the anime is of non-canonical content.
However, which anime title contains the most filler of them all -- and is making one’s way through it worthwhile in terms of how it serves the overall story, making that anime worth the watch even for beginner franchise fans? In some cases, the filler is important, whereas at other times, the filler is completely irrelevant to the main plot and does nothing to make it better.
What Are Filler Episodes?
Filler refers to the content of an anime that is not in the original manga. This is extra content that the studio creates, featuring exclusive scenes not created by the manga author. Filler episodes can serve several purposes, but it is typically used when the anime catches up to the manga. When the manga artist hasn't produced enough new chapters to their series, the anime production may create new episodes to give the author more time to further their story.
However, filler usually does not continue the story, so the episodes deviate from the original storyline. The most filler can do is expand upon the story by further exploring the characters and the world they live in. As a result, filler episodes may feel somewhat random or don't seem to add anything to the protagonist's story. In some shows, filler tends to overlap with the original series. For example, many filler episodes in Pokémon and Detective Conan add extra adventures for the main characters to embark on that don't stray too far from the main plot.
Mixed-Canon Versus Non-Canon Filler
Filler in anime tends to fall within three categories: manga canon, mixed-canon filler and non-canon filler. Canon refers to anything that incorporates the original manga. The content is taken directly from the manga and turned into an anime. It follows the original events as if pulled from the page. Mixed canon is filler episodes that contain some additional aspect that was not in the manga. While it does take scenes from the manga, there may be some scenes or even characters that are anime-only. Due to it containing details from the manga, it is suggested to watch the mixed-canon filler to fully understand the anime.
Non-canon filler is any filler that was not in the original manga and may not be necessary to watch. Websites such as Anime Filler List break down different series by episode. It separates the episodes by category to let fans know which episodes are canon or filler. Fans can then decide whether they want to skip certain episodes as they go.
Which Anime Has the Most Filler?
The three series with the highest filler count in terms of the number of episodes alone are Detective Conan with 440 filler episodes, Naruto and Naruto Shippuden with 294 and Pokémon with 231. Since these anime are longer-running series, their original manga has been published for decades longer than recent series, such as My Hero Academia or Jujutsu Kaisen, and have had more air time. As a result, they have more episodes and more potential for filler. However, compared to shorter series, Detective Conan, Naruto and Pokémon's filler percentages are actually less than expected. The Naruto series has 770 episodes and is 38% filler, whereas Sailor Moon has 98 filler episodes out of 200, making it have a whopping 46% filler.
Many fans may skip filler episodes due to their irrelevance, but some filler should be watched. Mixed-canon filler can include content that is vital to understanding the story. Therefore, skipping it may leave the viewer confused. However, even filler that is non-canon may not be necessary to watch but can still be entertaining, as it can showcase side stories that add adventures for beloved protagonists.