Episode 46

Yoriichi Type Zero (緑壱零式) is the 46th episode of the Kimetsu no Yaiba TV anime series, and the 2nd episode of its third season.

Plot
The young swordsmith continues to refuse Muichiro’s request for a key, as well as claiming he would not show how to use “it”. As Tanjiro watches the argument behind the trees, believing he should mediate, the annoyed Mist Hashira chops at the boy’s neck, rendering him unconscious. Tanjiro rushes in and confronts Muichiro, demanding he let go; he attempts to pull his hand away from the smith but cannot move the Hashira’s arm despite him being smaller and thinner. Muichiro instead demands that he let go and elbows the Demon Slayer’s stomach, sending him to the ground in pain. He insults Tanjiro for being weak and wonders how he entered the Corps, before he senses a demon inside the box he is carrying.

Tanjiro swats his hand away and demands he does not touch it. He pulls the young smith from Muichiro’s hold, somewhat surprising him, but the upset swordsmith refuses Tanjiro’s help and declares again he would not give the key, believing the item he is worried about will break. Muichiro insults him for believing he could hold out on such circumstances and reasons that he could made another one. He asks how many people might have died in the time he is refusing to give up something trivial and remarks that a Hashira’s time is more valuable than his; since he cannot fight, all a swordsmith is good for is making weapons.

Muichiro asks for the key once more, only for Tanjiro to step in to defend the smith. The frustrated Demon Slayer claims that he cannot stand the Hashira's demeanor, and while he concurs with his statements, he adds that a swordsmith’s job is still vital, as a swordsman and a swordsmith cannot exist without each other. Muichiro suddenly cuts him off and states that he has no time to listen to a “boring speech”, before chopping at Tanjiro’s neck to knock him out.

Some time later, Tanjiro eventually wakes up, asking if Haganezuka had been around, but the swordsmith states that he is not. Tanjiro then asks for Muichiro's whereabouts, and the smith states that he gave him the key to fend him away. Though he is dismayed he interjected in a hopeless argument, the boy thanks Tanjiro for defending him. He then asks about the man with them but is told it was a mechanical doll, which needed the key. The smith states that the combat doll is capable of 108 movements and can overpower a person, before two then hear a loud clash, with the smith realizing that Muichiro has activated it. Tanjiro and the swordsmith watch as Muichiro engages the battle doll in a rapid skirmish. The smith states that it was built by his ancestors and is known as Yoriichi Type Zero. Tanjiro asks why it has six arms and the boy responds that according to his father, the doll is based on a real person but six arms was needed to replicate how fast the person's movement was. Looking at the doll's face, Tanjiro recognizes it but cannot pinpoint its familiarity, asking the smith who the person was, but even he does not know as the person was from the Sengoku Period. Amazed at 300 year old technology still not replicated now, the smith then solemnly notes that if it was to be broken, it cannot be fix by anyone. As Tanjiro watches Muichiro fight, he is amazed at someone so young being so talented.

Suddenly, a shrill voice comments that Muichiro is a descendant of the wielder of Sun Breathing; it is Muichiro's Kasugai Crow. When Tanjiro notes that the Hashira doesn't use Sun Breathing, the crow bites him for insulting her owner. The Demon Slayer then notes that he saw the man in a dream but the crow lambasts his claims that he knows someone from the Sengoku Period. The smith then realizes that he perhaps saw an inherited memory, and possibly one of his ancestor's. Happy that his claims are not out of proportions, Tanjiro asks for the boy's name, who replies he is Kotetsu. They then hear a loud crash as Muichiro lands a blow on the doll, causing extensive damage. Seeing this, Kotetsu runs away in anguish.

Using his sense of smell, Tanjiro eventually locates Kotetsu up in a tree and offer his help, while asking that he don't give up on the doll. He states that he must try for his future self but Kotetsu refuses to continue, believing all his generation's accomplishments will end with him. Suddenly, he notices Tanjiro hanging by a branch and is flicked in the chin, shocked and amazed that the Demon Slayer climbed up quickly and silently. Tanjiro claims that even when he cannot do something now, someone will help him. Even if it is something beyond him now, his descendants will eventually do it. Tanjiro proclaims his desire to defeat Muzan Kibutsuji and save Nezuko but even he could die before fulfilling it, yet he remains hopeful someone will do it for him. Clutching Kotetsu's hand, the Demon Slayer declares that they do their best together, bring the young swordsmith to tears and inspiring him to continue.

As they walk back to the doll, they notices Muichiro now on his way, having finished what he believed was a successful training session. The Mist Hashira then mentions that his own sword was snapped in training and he will now be using one from the doll, holding a broken off arm with a blade. Kotetsu then hurries to the doll while Muichiro orders Tanjiro to dispose of his old sword, tossing it at his head. Seeing his dismissive actions, Tanjiro notes that he does not bear any malice and seems to not be doing it on purposes, though remarks that the same cannot be said of his crow. As rain falls, the smith dejectedly looks at the damaged doll but Tanjiro wants to test if it is still functional. Setting up upright and turning the key, they are amazed to see that Yoriichi Type Zero still works. Still angered by Muichiro, Kotetsu then desires for Tanjiro to train with the doll in the hope of surpassing the Mist Hashira.

Even while fighting the doll now armed with wooden clubs, Tanjiro is overwhelmed by its speed and unable to land a hit. Moreover, in spite of his earlier inability to defend himself, seeing a way to beat Muichiro at his own game reveals that Kotetsu is both hotheaded and keenly analytical, insulting the Hashira in front of the Demon Slayer and teaching him on his errors in engaging it.

Characters in Order of Appearance

 * Muichiro Tokito
 * Kotetsu
 * Tanjiro Kamado
 * Yoriichi Type Zero