of the Demon Slayer The last installment came in 2025, when the series began its final trilogy with Infinity Castle Part 1 — Akaja's Return. A year has passed since that movie, but we haven't received an official update about the release date of the next movie. However, we're still extremely excited for these new movies, and for those who read the manga, we can't wait to see the final adaptation of the series, that of Tanjiro's Demon King form.
At the end of Demon Slayer, Tanjiro is transformed into the Demon King by Muzan, and he becomes the strongest character in the entire world. This transformation eventually backfires, but for a brief moment, it gives birth to a much stronger character than the likes of Muzan or Yorichi. The Demon Slayer anime by Ufotable is lining up this form for a 2029 release, when Infinity Castle Part 3 hits theaters.
Demon Slayer: Infinity Castle Part 3 is set to unveil Tanjiro's Demon King transformation, making him the strongest ever.
Demon Slayer The series has been going strong since 2019 when it received its first TV anime through Ufotable Studios. Since then we've gotten a second, third and fourth season as well as three movies. The last movie was Demon Slayer: Infinity Castle Part 1, which was officially released on July 18, 2025, and after that, we're getting two more movies to conclude the Demon Slayer trilogy. There are two more movies planned, now known as Infinity Castle Part 2 and Infinity Castle Part 3, and of course, Part 3 will be the feature with the highest stakes, and for big reasons. Infinity Castle Part 3 will mark the beginning of the final battle against Muzan. Of course, as with any shonen story, by the end of the battle, the demon slayers will find a way to subdue the villain, even if it comes with a great sacrifice.
Looking at the manga, we saw the fall of Muzan in Demon Slayer chapter 200, which was released in Weekly Shonen Jump issue #18 on March 30, 2020. But to everyone's shock, that wasn't the end of her. Before Muzan's body completely disintegrates, he decides to donate his blood and living cells to Tanjiro, the protagonist of the story. This development takes place in Demon Slayer Chapter 201 in Shuisha's Weekly Shonen Jump Issue #19 dated April 6, 2020. Muzan's blood transfusion initiates a demonic transformation within Tanjiro, who was officially known as Demon King Tanjiro.
In this form, Tanjiro is basically changing to become a new Muzan. This form of Tanjiro would prove to be a greater threat to the world than Muzan, making him one of the strongest characters of all time. Arguably, this form is Tanjiro's strongest, as well as the strongest transformation in the entire story. In this form, Tanjiro develops ghost-like traits, such as slanted eyes and jagged teeth. He also has flame-shaped markings on his body, as we see with Muzan's final form, or Kokushibo.
“My body will soon hang in the sunlight… But, my memories are also eternal and indestructible. I will also transfer my memories to this boy. My breath and heart are leaving, but all my cells are not destroyed. There is still time. I will pour all my blood and strength into him. Thus, I will not lose, I will not lose to the sun, I will be with Tanjiro. Because of your blood, you can use demonic breathing techniques. – Muzan to Tanjiro in Demon Slayer Chapter 201
As far as the manga is concerned, Demon Slayer Chapter 203, released on April 27, 2020, in Shuisha's Weekly Shōnen Jump double issue #21-22, sees the transformation reversed through the cumulative efforts of Nezuko, Kanao, and Shinobu.
Using the flower's breathing final form: Vermillion Eye, Kanao is able to inject Tanjiro with the anti-demon antidote given to him by Shinobu, while Nezuko captures him and tries to talk him out of the remaining humanity he has left in him before fully transforming. Tanjiro also rejects Muzan and regains his mind, and he rises as a human once more. Of course, while Tanjiro's form was pretty strong, he was left with great debuffs after resisting. Tanjiro is permanently blind in one eye, and the hand he regenerates resembles that of an elder, as he is unable to move it properly.
All the powers and abilities of the Demon King Tanjiro
Because of how quickly Tanjiro turned into the Demon King Tanjiro and was liberated, we don't have the full range of his powers, since he never really went out. What we saw was not even a complete transformation. However, from Muzan's own performance, we know what kind of beast Tanjiro would have been in his base form as well. In the Sunrise arc, the demon slayers battled Muzan, and it was clear that he was no match for them with their sword slashes. This is for his resurrection, said to be the best of all demons. What is even more impressive is that Muzan's resurrection itself did not return to this moment. Muzan was also able to sprout tentacle-like limbs from his body and use them in battle. The same tentacles appear to sprout when Tanjiro transforms.
Through Muzan's own comments, we know that Tanjiro was much stronger than him, and in large part, it comes to the two abilities that Muzan never had. For one, Tanjiro, like Nezuko, would be a sun-resistant monster. The sun is the demon's main weakness, and these two defeated it. Muzan's ultimate goal was always to obtain the Sun Resistance, but he failed where Tanjiro succeeded. A demon king with resistance to the sun is simply invincible, as the only way for Muzan to fall was to hold him until sunrise.
Tanjiro has another powerful ability that Muzan does not have Sun Breath. Sun Breathing is the only other weakness that the Demon King can have, and thus Yorichi defeats Muzan. But Tanjiro's resistance to the sun and his own mastery of the sword style meant that even this would be useless against him.
Demon King Tanjiro is the strongest change in the series, eclipsing Muzan and Yorichi
Demon King Tanjiro is definitely the strongest character in Demon Slayer's story. Muzan stated that he would make Tanjiro the strongest demon king ever, and this is more than reflected in his powers and abilities that defy normal demon powers. What's more, in this form, Tanjiro undoubtedly surpasses even Yorichi, the progenitor of Sun Breathing and all breathing styles.
Yorichi was a talented swordsman like no other, and he was able to quickly defeat and almost kill Muzan at full power. If Yorichi and the Demon King Tanjiro were to face off, however, that kind of victory would not be possible. While Yorichi could stand up to the Demon King Tanjiro, he has no way of dealing a fatal blow to him. Due to Sun's resistance in Tanjiro, Sun Breathing would not be as effective and would not work even if it stopped until sunrise. Ultimately, Tanjiro will come out on top and defeat Yorichi.
Demon Slayer: Infinity Castle Part 1 is available to watch on Crunchyroll from July 28, 2026.
