Episode 49

Bright Red Blade (赫刀) is the 49th episode of the Kimetsu no Yaiba TV anime series, and the 5th episode of its third season.

Plot
As Muichiro carries Kotetsu on his shoulder, he asks if they are heading in the right direction, to which Kotetsu answers so. He soon spots a fish demon up ahead attempting to climb up a tree to reach Kozo; Muichiro rushes forward and slashes the demon’s vase, killing it and saving the swordsmith. Kotetsu and Kozo both express relief at seeing each other safe, while the Hashira asks if he is the one named Kanamori, questioning if his sword is complete. Kozo notices the one he is using is badly chipped and states that his own blade is indeed prepared.

He adds that Tanjiro had previously asked to understand him, which surprises Muichiro. Kotetsu then cuts off the discussion by stating that Hotaru is still in danger, which Kozo acknowledges and proceeds to lead the way. As they head deep into the forest, he points to a distant work hut and states that it contains a blade he can use, asking that he protect the village chief. Muichiro suddenly pulls the swordsmith back and notes that something is coming. A porcelain vase rolls out of the bushes and the voice inside is impressed he had noticed him. Gyokko emerges and notes that Muichiro is a Hashira.

As the Swordsmith Village is besieged by Gyokko’s Blood Demon Art fish demons, the villagers desperately rally themselves together and orders are given to protect the Hashira’s weapons and protect the chief. The demons begin to attack and kill them, while the swordsmith struggle to stave them off and survive; when one corners a group behind a house, the Love Hashira rushes in and slices through its vase, saving them. Mitsuri apologizes for being late and begins to kill all of the demons in rapid succession, to the smiths’ amazement. They call for the village chief to be saved and she makes her way to rescue him. At Tecchin Techikawahara’s residence, an enormous fish demon holds the chief in its grasp and begins to crush him to death. His aide attempts to save him but is knocked aside, while noticing that the Demon Slayers stationed to protect him have all been killed. Despite his efforts, the demon proves too big and fast for him to stand a chance. Mitsuri then appears before the aide and asks that he do not move due to internal injuries; he is amazed to see her strange whip-like Nichirin sword forged by Tecchin himself. As the demon roars in anger, Mitsuri uses Love Breathing, First Form: Shivers of First Love; using her whip sword, she speeds around its body and eviscerates the monster, killing it instantly.

She remarks that she cannot stand the unreasonable harm of others. The demon burns up and chief Tecchin nearly falls when its hand fades away. Mitsuri catches him and desperately asks if he is okay, to which he says he is now being held by a pretty young woman, causing her to playfully chide him. His aide makes an attempt at her attention but the chief does not want his moment ruined.

As Tanjiro begins to smell something unusual, he wakes up to see Nezuko carrying him and running away, as Sekido attempts to attack them with his lightning. He strikes down the building with multiple bolts and the siblings are soon caught in its path and stunned again. Despite the pain, Tanjiro looks up in time to see Urogi swooping down to attack them, rolling out of the demon's path and carrying Nezuko with him into the building. Sekido orders the area destroyed and Karaku gives chase after the Demon Slayers. He enters the building and spots them, swinging his uchiwa to launch a gust at them, though he misses when they turn at the corner.

Karaku catches them in a long hallway and summons an even more powerful gust of wind, destroying the entire structure and launching the siblings into the air. As they hurtle uncontrollably, Nezuko shocks Tanjiro by grabbing onto his blade. With the area levelled, Hantengu's manifestations begin to look for the siblings. With Nezuko trapped beneath heavy debris, Tanjiro asks that she wait as he attempts to free her, begging her to let go of his sword. She grips even harder and cuts her fingers, coating the blade in her blood. He watches as Sekido and Karaku look through the dust cloud, waiting to let it settle so that they can kill him, as Nezuko ignores her brother's demands and continues to grip his sword.

Gyokko introduces himself and asks Muichiro if he could have a word before killing him, as Kozo and Kotetsu stand behind him. The demon intends to show them a "creation" of his, which confuses Muichiro. Before them, a pot releases something that horrifies the three: a collection of the mangled bodies of swordsmiths with blades imbedded in them. Gyokko dubs his creation "The Death Throes of the Smiths" and showcases its features, such as the smiths' callused hands from hard labor and half broken masks. To their shock, Kozo and Kotetsu recognize all of the victims. Gyokko then displays one final features, demonstrating that by twisting a katana, they all scream in agony to show they are still alive, bringing Kotetsu and Kozo to tears.

An enraged Muichiro lunges forward and attempts to slash Upper Five's neck, only for the demon to duck back into his vase and appear at another atop the roof. Gyokko exasperatedly demands he be allowed to continue speaking but Muichiro leaps up and slashes the vase, noting that he sliced it with little resistance. A new vase appears on the ground and Gyokko curses the Hashira for destroying his old one. Muichiro notes that unlike Hantengu, who is not avoiding slashes to the neck, Gyokko is evading his attacks, indicating that he can be killed via decapitation. Gyokko forms a vase in his hand and summons two demon goldfish, before using Thousand Needle Fish Kill. The demons spit out hundreds of needles at Muichiro and forces him to move out of the way. As Kotetsu calls out to him, the demons notices the two smiths and spit their needles at them instead. To their shock, Muichiro stands before them and has taken multiple needles to the face and arms, before ordering them to hide and leave. The goldfish spit again and the Hashira blocks the needles' path to protect the two, who quickly leave the scene.

The demon is amused at the sight of the prickled Hashira, asking if he can feel the poison's paralysis setting in. Gyokko insults him for saving worthless lives only to lose his own. Unexpectedly, the words ring in Muichiro and he remembers when someone had told him that his life was worthless: the moment was in the summer, the door to their home was open due to the heat, and the cicadas were calling in the night. Gyokko becomes excited to make a new artwork out of the Hashira and Muichiro speeds forward, annoyed at his continual chatter. He swings at his neck but cannot cut into the demon's flesh, as Gyokko forms a new vase in his hand. Using Blood Demon Art: Water Prison Pot, Upper Five traps the Mist Hashira in a watery pot to suffocate him to death, believing such a demise is "stylish and beautiful" and remarking about his enjoyment in feeling his blade at his neck. Muichiro attempts to pierce through but cannot penetrate the pot, while Gyokko revels in stopping the Demon Slayer's greatest weapon, his breathing. He joyfully hopes to see his face as he dies and notes that by destroying the village, the Demon Slayers will be crippled and Kagaya Ubuyashik i's head can be taken.

Tanjiro continues to beg Nezuko to let go of his blade but she suddenly uses Exploding Blood and engulfs the weapon in her flames. He watches as it begins to change color into a bright red. A voice then comments on her amazement at seeing the blade of the "samurai" turn red as he fights, as Sumiyoshi watches. Tanjiro then realizes that he is seeing an inherited memory of his ancestor and the samurai the speaking girl had mentioned is the Demon Slayer who wears his earrings. His blade was black like his and it must have been able to turn red like his at the moment.

As he remarks that even when demons get stronger as he does, his body will still be vulnerable to injury, yet a life has continued to save him to continue living. The hopes and feelings of those who lent their strength are all the same; to defeat demons and save lives.

Ready to answer their feelings, Tanjiro steps forward to face Urogi, Karaku, and Sekido. Karaku is amused to see him with a new weapon and Urogi claims it will not help him further, flying to kill him. However, Sekido notices the bright red blade and through Muzan's memories in his cells, he realizes it belonged to the swordsman who cornered and nearly killed the Demon Progenitor. As the scar on his head burns into a fiery mark once more, Tanjiro raises his blade in preparation to strike. The images of the mysterious swordsman overlaps with Tanjiro, shocking Sekido and Urogi. Tanjiro uses Hinokami Kagura and instantly slashes through Urogi's neck; he then blitzes forward and sever Karaku's, before finally rushing toward Sekido and cutting through the demon's neck; the move Sun Halo Dragon Head Dance decapitating all three manifestations in a single fluid dragon-like attack. He remembers the moment when he had gain the strength to decapitate Gyutaro, how his breathing and strength had changed and the sensation of burning through his whole body and forehead.

Now assured he can kill the clones, he looks for the last demon, hoping to kill Hantengu by beheading all four. He quickly spots Genya in the forest with him and see he has already pinned Aizetsu with his own yari and beheaded him. However, when he calls out to him, Genya turns his head, revealing fangs in his mouth, bulging veins, and his eyes now black and yellow.