In Episode 3 of *Demon Slayer: Kimetsu no Yaiba* Season 3 (Swordsmith Village Arc), titled "A Sword from Over 300 Years Ago," the scene opens with Kotetsu and Tanjiro both recoiling in astonishment as they uncover the hidden sword nestled within Yoriichi Type Zero. Kotetsu's eyes sparkle with excitement at the prospect of Tanjiro wielding such a legendary blade, but Tanjiro himself is overcome with trepidation. A playful yet earnest debate ensues as they attempt to persuade one another of their contrasting viewpoints. Ultimately, they resolve to unsheathe the sword, only to be met with a wave of disappointment as they behold its rusty, neglected state.
Just then, a newly muscular and determined Hotaru Haganezuka bursts onto the scene, his sights set on claiming the sword for himself. Kotetsu and Tanjiro spring into action, desperately trying to thwart his intentions as they ponder his true motives. Suddenly, Kanamori intervenes, tickling Haganezuka until he succumbs to unconsciousness. With a smirk, Kanamori reveals that Haganezuka had been relentlessly training to forge an even stronger sword for Tanjiro, a revelation that touches Tanjiro deeply.
Haganezuka, regaining consciousness with a start, declares his resolve to restore the ancient sword for Tanjiro's use. Kotetsu, seizing the opportunity, scolds Haganezuka for his earlier vagueness. Infuriated, Haganezuka lunges at Kotetsu, only to be subdued once more by the combined efforts of Tanjiro and Kanamori, who resort to tickling him into submission. In a moment of clarity, Haganezuka hands Tanjiro a temporary sword and vows to return in three days with the newly polished, 300-year-old blade.
As dusk falls, Tanjiro finds himself worrying about Haganezuka's well-being and decides to voice his concerns to Genya. However, the other slayer remains uninterested in forging a friendship, still harboring resentment over Tanjiro breaking his arm during their final selection. In a moment of whimsy, Tanjiro notices that Genya had broken a tooth at the hot spring and had kept it, intending to return it. Genya, taken aback and slightly creeped out by the gesture, promptly kicks Tanjiro out of his room.
Undeterred, Tanjiro's mind races with ideas as he braids Nezuko's hair. A plan begins to form—a plan to bridge the gap between himself and Genya by sharing a meal together the following morning.
Meanwhile, a swordsmith makes his way back from the soothing hot springs, his eyes catching sight of a peculiar vase. Curiosity piqued, he approaches only to discover that it belongs to Gyokko, the potted demon. In a gruesome twist, Gyokko devours the swordsmith but promptly regurgitates him, disgusted by the taste. Yet, his malevolent intent remains unswayed; he vows to raze the village to the ground, reasoning that it would weaken the slayers who stand against Muzan's reign of terror.
Meanwhile, lurking on a rooftop, Hantengu devises a sinister plan to swiftly eliminate all who dare oppose Muzan. At that very moment, Genya enters a swordsmith's hut, seeking his weapon, only to find it deserted. A glint of steel catches his eye, and he is momentarily transported back to memories of his brother, Sanemi.
Elsewhere, Muichiro Tokito rouses Tanjiro from his slumber, eager for information about Kanamori. Tanjiro reveals that Kanamori is his new swordsmith, and offers to assist in the search. Tokito finds Tanjiro's inquisitiveness bothersome, but Tanjiro counters with a heartfelt sentiment: "Kindness begets kindness." Startled by the simplicity and depth of Tanjiro's words, Tokito demands a repetition. Just then, Nezuko interrupts, causing Tokito to lose his train of thought as he wonders if he has seen her before. Both siblings are equally puzzled by the encounter.
Their reverie is shattered by the sound of Hantengu's pathetic sobs as he slowly makes his entrance. Tokito lunges forward, sword drawn, but Hantengu is a blur of motion, deftly evading the attack. Nezuko attempts to lend a hand, but Tanjiro cautions her against transforming into her demon form, fearing it might exacerbate her condition. Tokito lands a decisive blow, severing Hantengu's head, but to their horror, the demon splits into two new entities: Sekido and Karaku. With a single, devastating move, Tokito is hurled back, while the other demon launches an assault on Tanjiro.
Genya arrives just in time, firing Nichirin bullets at the demons. He then slashes through one of their heads, only for it to split into two more demons. Tanjiro quickly deduces that every time Hantengu is decapitated, he spawns a new clone, each possessing unique abilities. As Tanjiro searches for Hantengu's Achilles' heel, a winged clone soars away with him in its grasp, while another clone stabs Genya. Tanjiro urges Nezuko to aid Genya, but the flying demon taunts him relentlessly. Tanjiro severs the leg holding him captive, but the clone retaliates with a barrage of soundwaves, sending him plummeting into the forest below.
Meanwhile, Tokito is racing back to the scene when he spots Kotetsu valiantly trying to fend off a demon. Tokito initially dismisses Kotetsu, asserting that a child's skills are negligible and that he should focus his efforts on those with greater prowess, like the chief swordsmith. However, Tanjiro's earlier words echo in his mind, prompting him to reconsider. Just as the demon is about to claim Kotetsu as its next meal, Tokito swoops in, rescuing the child from certain doom.
In the epilogue, Kotetsu expresses his frustration at Haganezuko's preoccupation with repairing a 300-year-old sword amidst the chaos. Tanjiro shares a charming anecdote about Haganezuko's childhood, revealing that wind chimes adorned his hat as a means to soothe his tantrums. Haganezuko appears, chastising them for treating him like a child. Yet, as they begin to play the wind chimes, he attempts to flee, only to be drawn back by the familiar, calming melody.
