You really kind of need to see Demon Slayer: Kimetsu no Yaiba's movie. No, that's not exactly right. You absolutely need to see it either while it's still making its run through theaters or it hits digitally later this Summer. Picking up immediately after the final moments of the first season's final episode, Demon Slayer -Kimetsu no Yaiba- The Movie: Mugen Train serves as a bridge between what came before and what's coming next in the anime. Because it directly adapts Koyoharu Gotouge's original manga series, it's an incredibly important piece of the series' puzzle.
Unlike other anime feature films that tell their own original stories either outside of the main canon or in between official canonical events, Mugen Train is legitimately the next step in the Demon Slayer: Kimetsu no Yaiba saga. Because of this, fans wanting to jump into the second season coming this Fall are going to absolutely need to know what happens in the movie.
Season 2 of the anime has been confirmed to return this Fall in Japan (and will likely be streaming with the same services outside of Japan that the first season had when it eventually premieres), and the first trailer and teaser poster for the new season has confirmed that it will be tackling the Entertainment District arc of the original manga series that comes right after the events of Mugen Train.
Mugen Train spends no time recapping the events of the first season in order to get right into the heart and action of the new arc, and that sets a precedent that the new season of the anime won't be spending much time on this either. Given its popularity in Japan and around the world, a fair assumption is that the anime will presume that fans have seen the movie just as the movie presumes you have already seen the first season.
So if you are going to want any context for the upcoming season, you'll need to either read the original manga the film is based on or check out the film yourself before Season 2 hits this Fall. Especially given some of the big cliffhangers still needing to be resolved be the end of Mugen Train's ride. Thankfully, if you do check out the film you're in for quite the wild ride.
It might be a requirement, but at least it's fun homework! But what do you think? Is seeing Demon Slayer's movie needed before the second season of the anime? Demon Slayer -Kimetsu no Yaiba- The Movie: Mugen Train is now screening in theaters, and you can check out our full review of the film here. Let us know your thoughts in the comments or you can even reach out to me directly about all things animated and other cool stuff @Valdezology on Twitter!