A sneaky Demon Slayer season 4 Easter egg has flown under the radar for two weeks, but eagle-eyed fans have finally cracked the code.

This cleverly hidden detail in the Hashira Training arc finale might tell the fate of your favorite Demon Slayers characters.

Tanjiro Kamado in Demon Slayer season 1, a featured image for ONE Esports article "Here are all Demon Slayer episodes from every season and where to watch them"
Credit: ONE Esports, ufotable, Koyoharu Gotouge
Here are all episodes of the anime from every season

The stakes are higher than ever as Tanjiro and his fellow swordsmen prepare to face even more powerful demons.

Buckle up because we’re about to dissect this exciting discovery and see what the future holds for Tanjiro Kamado, Zenitsu Agatsuma, Inosuke Hashibira, and the rest of the Hashira.

Warning: Major spoilers for those who haven’t watched the Demon Slayer season 4 finale or read the Final Arc of the Demon Slayer manga.

Demon Slayer season 4 Easter egg explained

Demon Slayer movie trilogy official poster for the Infinity Castle arc
Demon Slayer Infinity Castle arc movie trilogy’s first official poster

The explosive finale of Demon Slayer season 4 saw the Demon King Muzan Kibutsuji teleporting most of the Demon Slayer Corps into the heart of his domain, the Infinity Castle.

While all the major characters seemingly plummeted toward their fate, eagle-eyed fans with knowledge of the manga noticed a subtle but potentially significant detail.

Upper Rank Demons in ONE Esports featured image for article "Full list of the Twelve Demon Moons in Demon Slayer"
Credit: ONE Esports, ufotable, Koyoharu Gotouge
Full list of the Twelve Demon Moons

For some characters, including Tanjiro, Inosuke, Zenitsu, Wind Hashira Sanemi Shinazugawa, and Water Hashira Giyu Tomioka, the background illumination during their descent into the castle was a bright yellow light.

According to these fans, this color choice aligns with the events of the Demon Slayer manga, in which these characters ultimately survive the final battle against Muzan.

Demon Slayer watch order: How to watch the anime and movies in chronological order, a ONE Esports guide
Credit: ONE Esports, ufotable
How to watch the anime and movies in chronological order

However, other characters, namely Stone Hashira Gyomei Himejima, Love Hashira Mitsuri Kanroji, Serpent Hashira Obanai Iguro, Genya Shinazugawa, Mist Hashira Muichiro Tokito, and Insect Hashira Shinobu Kocho, were shown falling into a different section of the Infinity Castle bathed in a red light.

Here, the theory takes a more somber turn. In the manga, these characters tragically make the ultimate sacrifice during the final confrontation with Muzan.

While this detail hints at what’s to come, it’s important to remember that the Demon Slayer’s animation studio, ufotable, has made some changes to the anime, which we’ve seen in season 4.

Only time, and potentially future seasons of the Demon Slayer anime, will definitively reveal the fates of our favorite demon slayers.

READ MORE: Demon Slayer Infinity Castle movie trilogy is officially in development