Armed with his memories, Muichiro feels powerful and invincible, convinced that the demonic fifth moon has no chance against him.

Tanjiro, Nezuko, and Genya are struggling through an arduous battle against Zohakuten and his five tree dragons. They are forced to fight defensively against the tree dragons using the four emotion demon's powers, and Tanjiro is swallowed by one of them amidst the fight. Just as Tanjiro is close to meeting his demise, Mitsuri arrives in the nick of time and rescues him. And now, Mitsuri faces off against Zohakuten to rescue the captured Nezuko and Genya...!

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.

Tanjiro's next destination, according to his Kasugai Crow, is to the south-southeast. On the way, Tanjiro runs into his fellow Final Selection survivor, the swordsman Zenitsu Agatsuma. Tanjiro has a hard time dealing with Zenitsu's passive attitude as they head deep into the mountains. They encounter two children whose older brother was taken away right in front of their house. There, Zenitsu hears the sound of a tsuzumi ringing out from somewhere.

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...

During a silent night when the moon shines, Kagaya finally meets Muzan Kibutsuji, who appears at the Ubuyashiki Mansion.

After Tanjiro visits the Rengoku residence and meets Kyojuro's younger brother, Senjuro, to deliver Kyojuro's last message, Tanjiro spends his days training and completing missions. One day, he returns to the Butterfly Mansion to find Sound Hashira, Tengen Uzui, attempting to take Aoi and Naho away on a mission against their will. Tanjiro, Zenitsu and Inosuke offer to go on that mission instead, and they head to their next destination - the Entertainment District.

Two simultaneous fights continue, Tanjiro, Nezuko and Genya against Hantengu and Tokito against Gyokko. Genya began to show a demonic form. Tanjiro asks him to look for Hantengu's real body, but memories of the past begin to plague Genya.

After completing Mitsuri's training, Tanjiro heads to train with Iguro. When he arrives at the training site, Iguro is waiting for him, visibly angry. Will he be able to complete this horrifying training where he'll have to fix his sword skills?

Tokito continues advancing through the forest and finds Mr. Kanamori. As soon as they arrive at the work hut in the middle of the forest, they are welcomed by Gyokko. Meanwhile, Tanjiro continues his fight against Hantengu.

After a desperate fight to the death, Tanjiro prevails over Kyogai. He exits the house to find Zenitsu who had escaped earlier. But it is then that he sees the strange circumstances before him... The battered Zenitsu holding the box containing Nezuko in his arms while the man in the boar's head mask stands in the way with two Nichirin Swords drawn.

Tanjiro intervenes during an argument between a pillar and an apprentice blacksmith and learns of the existence of an amazing training method.

The injured Tanjiro, Zenitsu and Inosuke are sent to the home of the Insect Hashira, Shinobu Kocho, for treatment. Two weeks later, Tanjiro and Inosuke start rehabilitation training. But the drills are brutal, and they find themselves broken in spirit. Unaware of the grueling regimen, Zenitsu joins them late and is visibly enthusiastic in front of girls, but...

At Giyu Tomioka's urging, Tanjiro heads for Mt. Sagiri with his sister Nezuko who's been turned into a demon. During the night, Tanjiro catches the smell of blood from inside a temple. He enters, thinking that someone might be hurt, only to come upon a man-eating demon. When the demon attacks, Tanjiro manages to fight back with his hatchet, but the demon's strength is overwhelming. Just as the demon is about to finish him off, Tanjiro is saved by none other than.

Ubuyashiki, the leader of the Demon Slayer Corps, finally appears before Tanjiro. He tells him that he will allow Tanjiro and Nezuko to join the Corps. But the Hashiras are unable to accept this decision right away. The Wind Hashira, Sanemi Shinazugawa, slashes his own arm and taunts Nezuko with his blood, trying to get her to show her true colors as a demon.

Tanjiro, who's undergoing rehabilitation training at the Butterfly Mansion, works hard to keep up his Total Concentration Breathing techniques all day long. Though at first, he's helpless against Kanao, a swordswoman in his class who's training him, he slowly but surely begins to make some headway. Seeing Tanjiro devote himself to training every single day, Zenitsu and Inosuke resume training as well, but...

Tanjiro and Zenitsu head to Himejima's training site deep in the mountains and reunite with Inosuke and Murata. Tanjiro first starts the training by being hit by a waterfall but struggles with the coldness and weight of the water.

When day breaks, there are only four swordsmen left standing after the seven-day battle. The guides who greet Tanjiro and the other survivors explain the Demon Slayer Corps system. All four are issued uniforms and Kasugai Crows as messengers, after which they must select the ore for their own Nichirin swords. After gazing hard at each lump of ore, and using his keen sense of smell, the one Tanjiro chooses is...

Tanjiro is now clad in the uniform of the Demon Slayer Corps. His Nichirin Sword on his hip, and Nezuko, now awake, in a special box made by Urokodaki on his back, he heads out for his first assignment. A town to the northwest where girls have been vanishing nightly. There, Tanjiro meets Kazumi, haggard with worry after his girlfriend's been abducted. Though he does catch the scent of a demon nearby, there's just no demon in sight. Tanjiro is sure that a demon is behind this sinister incident...

Inside the house, where the rooms spin each time the tsuzumi is played, Tanjiro gets separated from Zenitsu Agatsuma. Without Tanjiro by his side, Zenitsu is overcome by fear and despair as he takes Shoichi through the house. Meanwhile, Tanjiro meets the master of the house, the tsuzumi-playing demon, and an odd-looking man wearing a boar’s head mask.

Their next destination is to the north-northwest. Tanjiro and Nezuko head towards Mount Natagumo with Zenitsu and Inosuke. This mountain is covered with spider webs and is swarming with innumerable spiders. Leaving the cowering Zenitsu behind, Tanjiro and Inosuke head up the mountain where they run into fellow Demon Slayers entangled in spider webs.

Tanjiro's group, fresh from completing their training at the Butterfly Mansion, head to their next mission, the Mugen Train. There they rendezvous with Rengoku, who arrived ahead of them. Tanjiro is overwhelmed by the always-energetic Rengoku, Zenitsu is frightened by the prospect of facing demons as usual, and Inosuke is immensely excited by the sight of the huge machine. But on this train loaded with passengers, a new battle is about to begin.

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 him in person.

The Hashira, Sanemi and Iguro, along with their comrades head to an abandoned castle on top of a mountain for a mission, while Tanjiro is being treated at the Butterfly Mansion for the wounds he suffered at the Swordsmith Village. Later on, the Hashira gather at the Ubuyashiki Mansion to hold a Hashira meeting, where Muichiro reveals how the marks manifested. In an effort to strengthen the entire Demon Slayer Corps from the bottom up, the Hashira Training begins...

Kagaya's Kasugai Crow suddenly appears in front of Tamayo and invites her to the Demon Slayer headquarters — even though she is a demon. Meanwhile, after receiving a letter from Kagaya at the Butterfly Mansion, Tanjiro pays a visit to Giyu, who is not participating in the Hashira Training. At first, Tanjiro is rejected by Giyu but patiently continues to try to talk to him. Giyu, who gives in to Tanjiro's persistence, begins to share the reason why he won't participate in the training.