Kanata Kamado tries to wake his younger brother Sumihiko up, saying he would be late for school. Sumihiko groggily responds that he is already up but Kanata sees that he is barely awake and leaves for school by himself.
Yoshiteru Agatsuma reads 'The Legend of Zenitsu,' the autobiography of his great-grandfather Zenitsu Agatsuma and cries when he reaches the part where they defeated Muzan Kibutsuji. Suddenly, his sister Toko, who resembles Nezuko, kicks Yoshiteru in the back and tells him to stop reading their great grandfather's novel of lies and to focus on his studies as his grades had been unruly low. He objects and says that the Demon Slayers had been very cool but Toko cuts him off and twists his ear, telling him to be cool like them and go study to get better grades.
As the two of them make their way to school together, Yoshiteru thinks to himself how the other women in his family were all quiet and polite but Toko was nothing like them. With an annoyed expression he asks Toko if she believes in reincarnation and she merely snaps at him asking what he was making such an expression for. Yoshiteru then says he believed that everyone who had died fighting Demons for a peaceful world had been reincarnated to live a peaceful life.
Toko ignores him and looks at a news alert with admiration on her phone, which declared that an athlete called Tenma Uzui had won a gold medal in gymnastics for Japan. Yoshiteru says that Tenma was rude and nasty but Toko defends him and he says that it truly was possible to get away with anything if one was good looking.
Another news story catches Yoshiteru's eye and he snatches Toko's phone from her, much to her irritation. He opens the story about a fair looking botanist called Aoba Hashibira who had discovered a rare flower called the Blue Spider Lily, which only bloomed during the daytime for two to three days every year. Aoba had come under intense criticism following a mistake in their handling of the lilies which caused them all to wither, and was forced to apologize at a press conference. Yoshiteru decries this attitude towards such a beautiful woman but Toko corrects him and tells him that Aoba is in fact a man, much to his shock and disgust.
The pair then encounter a woman pushing two strollers with twin children in them. They were wrapped in cloud patterned blankets and had black hair, reminiscent of the Tokito twins Muichiro and Yuichiro. Yoshiteru asks if the twins are girls and Toko says he is always creepy to which he cries out and declares that he is not creepy at all.
The two then pass a pair of female students and Yoshiteru immediately recognizes that they are from the nearby Sekirei Women's Academy, with two students being exact likenesses of Kanae Kocho and Shinobu Kocho. Toko looks at her brother in disappointment but is quickly distracted when she spots Kanata and eagerly runs over to tell him he looked cute with Kanata returning the compliment to her delight.
Yoshiteru mutters that he has been learning how to cast curses so they should watch out and Toko angrily asks him what he had said to which he whimpers an apology. They then cross next to the kindergarten and Yoshiteru stares at the teacher, who looked exactly like Gyomei Himejima but also notes that he looked funny in his pink apron. Toko asks Kanata if he wants to go with her to a certain diner on their way home. Kanata asks if she meant the one with the snake decor and the giant serving sizes, which Toko confirms and Kanata responds that he is unsure if he could ever show his face there again.
He then tells her how the last time he had been there with Yoshiteru, the boy had kept staring at the chest of the woman who worked there, who resembles Mitsuri and her husband who worked their in the kitchen had thrown a knife at them. Her husband resembles Obanai. Toko turns around to Yoshiteru in disgust and rage, as the boy stammers that this was a false accusation.
Back at the Kamado household, Sumihiko finally wakes up and notices that he was running late, wondering why no one had woken him up. He then gets ready for school and parkours his way out of his window to the bottom of their apartment and sprints for his school. On his way he passes through a house with two elderly men playing shogi, bearing resemblance to and wearing robes similar to those of Sakonji and Jigoro, the one wearing Jigoro's robes yells out at Sumihiko, asking him why he did this every morning. Meanwhile on the old men's television, a news report began about an Ubuyashiki who had set the record for eldest living Japanese person. This Ubuyashiki is actually Kiriya Ubuyashiki, who became the master after his father, Kagaya Ubuyashiki, died during the beginning of the Infinity Castle Arc.
Sumihiko continues his race, and on the way, he runs past a store called 'Haganezuka Maintenance' and also three girls who recognized him as the running guy. The girls, who resemble Sumi, Kiyo and Naho giggle, as Sumihiko continues his run. Arriving at a traffic light that had just gone green, Sumihiko attempts to jump over the hood of a police car to avoid having to stop. He startles the policemen inside, who are Sanehiro Shinazugawa and the reincarnation of Genya Shinazugawa. Sanehiro is incensed and believes that Sumihiko must be the one they had received seven reports of. They begin to go after him and Sumihiko runs even faster.
He crosses a group of three children, including Giichi Tomioka and the reincarnation of Sabito and Makomo. The boys have a rare toy shaped like the masks once made by Sakonji for his pupils with the girl saying she had run out of her allowance. The boys offer her their own so that she may also be able to get one of her own and she is overjoyed and embarrassed at their generosity.
At the school, Yoshiteru watches as a boy named Goto looks at his phone at an image of a beautiful woman who looks just like Tamayo. Yoshiteru interrupts the boy and his friend and says that he recognizes this as one of the paintings of Yushiro Yamamoto which is Yushiro's alias. He had begun to receive acclaim throughout the world for his paintings of Tamayo, which were said to be like photographs. Yoshiteru notes however, that Yushiro would attempt to shoot any reporters who came to ask him questions. Saying that his first love was No. 812 Tamayo with dark blue flowers, Yoshiteru walks off leaving the two boys bewildered at him.
Sumihiko continues to run and is joined by Tojuro, who is Senjuro Rengoku's descendant. Greeting the boy, Sumihiko says that it is unusual for him to be late and Tojuro explains that he had woken up at 4am but had gotten absorbed into his training. He says that he couldn't hear anything until his father whacked him and suddenly the police car draws nearer to the boys, asking for Sumihiko to stop. Tojuro says that Sumihiko should get into a sport but the boy responds that it would cut into his sleep with Tojuro being adamant that he would be great at whatever he picked.
The two continue to run, with the police car asking for them to stop as they arrive at their high school where a teacher, who looks like Murata, asks for the gate to be closed as soon as he sees Sumihiko. The person at the gate says that there are still three minutes until it should close but the teacher insists, saying that Sumihiko was a habitual offender. As the gate begins to shut, Sumihiko says he believes they will make it and Tojuro agrees. Both of them somersault over the gate and land inside the school, running for their classes. The police car comes to a halt and Sanehiro walks over to the gate and tells the teacher that they need to talk.
Aoba sits on a bench in the park, noting how it is a quiet day but the lab might fire him and wishes he could live a quiet life alone in the mountains. Back at the Kamado residence, Sumihiko's mother receives a phone call and is told of his doings, being highly surprised and apologizing for the trouble her son caused. On the wall next to her there hung many photos and a katana that is actually Tanjiro's Nichirin Blade with Kyojuro's flame hilt. Just above the blade hangs an old, yellowing picture of all those who had survived the battle against Muzan and the two hanafuda earrings of Yoriichi Tsugikuni as the series ends.
Characters in Order of Appearance
- Those who have died or fought against the Demons are all either reincarnated and/or have descendants/people who are just lookalikes, living normal lives with varying fortunes. See here for more details.
- Tanjiro and Kanao have great, great-grandchildren Sumihiko and Kanata.
- Zenitsu and Nezuko have great-grandchildren Toko and Yoshiteru.
- Inosuke and Aoi has a descendant named Aoba, a botanist who discovers the blue spider lilies sought by Muzan but is left disgraced as they wither and die.
- Shinobu and Kanae are reincarnated as academy students.
- Giyu's reincarnation/descendant is a child named Giichi, who is close friends with Sabito and Makomo's reincarnations.
- Tengen has a reincarnation/descendant named Tenma, an athlete who wins a gold medal in gymnastics.
- The Tokito brothers are reincarnated as young twins.
- Kozo and Kotetsu's reincarnations/descendants are seen as students.
- Gyomei is reincarnated as a kindergarten teacher.
- Obanai and Mitsuri are reincarnated and married, working at a diner.
- Sakonji and Jigoro are reincarnated as old men, seen playing a game of shogi.
- Kiriya Ubuyashiki holds the record for the longest living Japanese person.
- There is a store in town called the Haganezuka Maintenance store.
- Sumi, Naho, and Kiyo's reincarnations/descendants are seen as young students.
- Genya Shinazugawa's reincarnation and his brother Sanemi's reincarnation/descendant, Sanehiro, are policemen.
- Goto's reincarnation/descendant is a student, who is friends with Takeuchi's reincarnation/descendant.
- Yushiro and Chachamaru are still alive, with the former becoming famous for his lifelike paintings of Tamayo.
- Tojuro is a student who is either a reincarnation of Kyojuro or a descendant of Senjuro, possibly both.
- Murata's reincarnation/descendant is a school principal.
- The woman on Goto’s phone resembling Tamayo is her lookalike since demon’s can’t be reincarnated.
- Volume 23 includes an extra fourteen pages of content for the final chapter that were initially cut from the chapter release.