The contest for the most popular character in the hit anime, Demon Slayer: Kimetsu no Yaiba, is tough. Whether it’s the red-and-yellow haired swordsman Kyojuro Rengoku, or the ghostly Shinobu Kocho with empty purple eyes, the action series has no shortage of memorable (and visually striking) heroes.
But now even the most powerful swordsmen in the series have now met their match, thanks to the new characters introduced in the latest episode. Who is the latest star that has managed to squeak its way into the hearts of fans? Well, it’s not a single character, but a team of really buff mice called Ninju.
The critters appear in the fourth episode of the latest season, the Entertainment District Arc. This part of the story follows Tanjiro Kamado and friends as they venture into a bustling city with robust nightlife. There, they meet their next mentor, a powerful Sound Hashira named Tengen Uzui. This mentor does more than bring his own giant rippling muscles to the Demon Slayer Corps — he also introduces Kamado to the mice that serve as his familiars and offer their aid to the characters.
The designs for the mice are as hilarious as they are cute — their look is based off of their master, Uzui. The two mice wear the same headband as Uzui, and as their name suggests, they have arms and chests so swollen that their muscles exceed the size of their torso and legs by several times. According to a post-credits scene, Uzui says that the Demon Slayer Corps only picks the most dedicated mice for the role, but “being narcissistic enough to fall in love with their own muscles is also a must.”
The rodents have captured the admiration of many fans online. Before the latest episode did the full reveal, the characters were shown running behind Inosuke in the opening title theme. After seeing them, fans wrote about how excited they were for the full reveal, saying, “I CAN’T WAIT TO SEE THEM.”
When we see the mice appear for the first time, Kamado’s friend, the boar-headed Inosuke, calls on the creatures to bring him his swords for battle. It’s a glorious scene during which Inosuke does a sitting jump and busts his head through the ceiling of a beautiful home to call upon the mice. The mice march through the attic of the building, chanting “Muscle! Muscle! Muscle!” as the two carry the swords (which are several times their size) to Inosuke.
Now that the Ninju have fully arrived in the series, fans have made fan art and edited fan videos using footage of them.
TikTokers have also joked about how these mice inspired their own fitness goals.
Other TikTokers have said they think the muscle mice are just straight-up better and cooler than the Hashira, which are among the most powerful fighters in the world of Demon Slayer.
At the time of publication, four episodes of The Entertainment District Arc of Demon Slayer have been released. The episodes air weekly, and the most recent episodes of Demon Slayer are currently available to stream on Crunchyroll, Funimation, or Hulu.