Demon Slayer: Kimetsu no Yaiba : Season 4

An Upper Rank Demon has been defeated for the first time in a hundred years by Uzui, Tanjiro, and his comrades' effort. This news causes a ripple effect not only among the members of the Demon Slayer Corps, but also the Upper Rank Demons, who have been summoned by Muzan Kibutsuji. Meanwhile, Tanjiro is recovering at the Butterfly Mansion when he discovers that he has upset his swordsmith Haganezuka after chipping his sword and decides to head to the village where the swordsmiths live to talk to

Tanjiro encounters Mist Hashira Muichiro Tokito and Kotetsu, a boy from the village, arguing. Muichiro is demanding that a “certain key” be handed over to him from Kotetsu. Being unable to look on in silence, Tanjiro intervenes to speak on behalf of Kotetsu, however Muichiro refuses to listen. According to Kotetsu, the key is used to operate a battle-type Mechanical Doll, Yoriichi Type Zero, that mimics the movement of a certain real-life swordsman...

Tanjiro begins his training with Yoriichi Type Zero and is pushed to the limits by Kotetsu's relentless coaching and extreme training. Through this experience, Tanjiro masters a new skill of predicting where the opponent's next move will hit by using his sense of smell. During his training, Tanjiro lands a blow on Yoriichi Type Zero and ends up destroying it, but a sword from over 300 years ago appears from inside...

Hantengu's head is slashed by Muichiro and he splits into two clones. Muichiro is blown away by Karaku. Tanjiro, Nezuko and Genya are stunned when the clones split into more clones. Muichiro rescues Kotetsu from a Goldfish Demon.

Upon arriving to the village, Mitsuri rushes to the chief of the village, Tecchin, and finds that all of his guards have been defeated and he himself is in a life-or-death situation. Muichiro is being guided by Kanamori, whom he rescued along the way, to the studio to receive his sword. However, Upper Five Gyokko is waiting in front of the studio, where Haganezuka is also working...

Muichiro is driven into a corner as he is trapped in water by Gyokko's Blood Demon Art amidst their battle. Meanwhile, Tanjiro and his comrades have successfully severed the necks of the four demons, but seeing that they haven't turned to dust, they realize that they cannot be defeated just by having their necks severed simultaneously. At that moment, Tanjiro senses the presence of a fifth demon as Genya aims for its neck...

Genya aims for the neck of the fifth demon that split off from Hantengu, but the demon's neck is shockingly hard, and his sword snaps in half in his attempt to strike it. His gun is also ineffective and Genya is driven into a corner. Realizing that he is unable to sever the neck by himself, he entrusts defeating the fifth demon, which is believed to be the main body, to Tanjiro. Taking on Genya's will, Tanjiro wields his sword against the fleeing demon...