Demon Slayer has become one of the biggest and most renowned anime franchises ever. The massive success of this series began with its first anime season, which aired back in 2019, but it went on to reach a whole new level of popularity after the release of its first movie, Demon Slayer: The Mugen Train. This movie went on to change the industry and became the biggest hit in Japanese box office history. The number one spot of The Mugen Train was, however, recently surpassed by another movie after 5 years of holding onto this title. The new number 1 movie in Japan is now another Demon Slayer movie—Demon Slayer: Infinity Castle Part 1 Akaza’s Return. Demon Slayer’s success is only growing, and the only movies that can surpass its previous hits are its own new movies.
Demon Slayer: Mugen Train Lost Its Number 1 Spot at The Box Office

- Mugen Train Was Surpassed by Demon Slayer: Infinity Castle
- Demon Slayer Holds Both Number 1 and 2 Spots
Demon Slayer: Mugen Train first premiered back in 2020, and its success was mind-blowing. This canon movie covered one of Demon Slayer’s manga arcs, the Mugen Train arc. This was quite a surprise, as most series produce movies and go out of their way to make them non-canon. For Demon Slayer, this proved to be a great decision. Mugen Train quickly became Japan’s biggest hit at the box office, beating the previous record holder of almost two decades, Spirited Away. Demon Slayer: Mugen Train was a phenomenon, both in Japan and even abroad. But now, 5 years after its release, it has been beaten, and Japan has a new number 1 movie.
The strong should aid and protect the weak. Then, the weak will become strong, and they in turn will aid and protect those weaker than them. That is the law of nature. - Tanjiro
The most shocking part is that it was beaten by a movie from its own franchise, and as fans know already, that's Demon Slayer: Infinity Castle Part 1—Akaza’s Return. This is quite incredible, and goes to show how Demon Slayer’s only competition has been itself.

Rengoku didn't lose! He didn't let anybody die! He fought to the end! He protected them to the end! You're the one who lost! It's Rengoku who won! - Rengoku
Can Any Movie Surpass Demon Slayer: Infinity Castle Part 1 Akaza’s Return?
Demon Slayer Infinity Castle Part 2 and Part 3 Have A Shot At Doing That

With Demon Slayer: Infinity Castle Part 1—Akaza’s Return becoming Japan’s number one movie now, fans are wondering if there’s any movie out there that could potentially dethrone it, and indeed, there is.
Demon Slayer: Infinity Castle Part 1—Akaza’s Return is big, but it’s only the first movie in a trilogy that will see the conclusion of Demon Slayer with its craziest arc yet. Akaza’s Return is just the beginning, and events are only going to heat up from here onwards.
You misunderstand, Tanjiro. I only despise the weak. I only spit on weaklings. Yes. Weaklings make me sick. It is the law of nature that they be weeded out. - Akaza to Tanjiro
It’s debatable whether Part 2 will surpass Part 1, but it’s definitely a possibility. However, Part 3 will almost surely become Japan’s number one once it drops. After all, it will feature the long-awaited battle against Muzan.

Demon Slayer: Infinity Castle is out in theatres right now. Fans who don’t want to wait for the movies to drop can check the manga out on Manga Plus. Meanwhile, for the anime, the series currently has 4 anime seasons. These anime seasons can all be found on Crunchyroll. The remainder of the series will, however, be animated into movies, which fans will have to wait for their theatrical release to watch, depending on their country.