The anime follows a boy named Tanjiro Kamado, a kind and hardworking child, living with his mother and siblings in the mountains away from the city. After his father’s demise he started to support his family by selling charcoal in the nearby town at the foothill of the mountain.
One day, after selling the charcoal and going back to his home at night he was advised by Saburo, an elderly person of the town, to stay at his home and not to travel alone at night. Next day, when he returned home he was shocked to see his entire family except his sister Nezuko murdered. Unable to comprehend what had happened to his family and desperately trying to save his sister, Tanjiro hurried down the mountain when Nezuko transforms into a demon and attacks Tanjiro.
Tanjiro Kamado’s encounter with Tomioka Giyuu
When Nezuko was attacking Tanjiro Kamado, a demon slayer Tomioka Giyuu tries to behead Nezuko who had became a demon. But at the nick of time Tanjiro was able to save her. Tanjiro pleaded Tomioka to leave Nezuko alive and told him that she was different from other demons and has not eaten any human but Tomioka was not convinced and tried to kill Nezuko.
In desperate attempts by Tanjiro Kamado to save Nezuko from Giyuu, Giyu noticed that the siblings had something special and different and as a demon Nezuko was different and hence spared them.
In search of Urokodaki Sakonji
While travelling in search of Urokodaki on Tomioka’s advice, Tanjiro Kamado and Nezuko encounters a demon who was eating a human. During the battle with the demon somehow Nezuko and Kamado were able to restrain the demon but Kamado was not able to kill the demon because of his kind nature. That is when Urokodaki arrives and makes Kamado realize his indecisiveness may cause great harm.
Urokodaki asks Kamado to steel his resolve since he was going to test if Kamado will be able to join Demon Slayer Corps and will nominate his name for Final Selection Test only if he passes Urokodaki’s test. After Kamado Tanjiro passes Urokodaki’s test he is accepted as Urokodaki’s apprentice. Urokodaki teaches Kamado various things along with 10 of the Water Style Breathing Techniques.
Tanjiro Kamado’s First Mission
After Kamado’s Final Selection Test, where 4 others had qualified the test were asked to select an ore for their Sun Blade and each were assigned a Kasugai Crow for communication. After which Kamado went back to Mt. Sagiri to Urokodaki. Soon Kamado got his first mission to go to nearby town in the Northwest and investigate the case of missing young girls.
On investigating Tanjiro Kamado finds that a demon is abducting young girls of age 16 and eating them.Collection information from a victim, he soon finds out the demon and slays him but still he wasn’t able to get any information about Muzan { the first demon}.
Encounter with Tamayo and Yushirou
While on his second mission in Tokyo, Tanjiro Kamado witnesses Muzan turning a person into demon but in efforts of saving that person Tanjiro couldn’t pursue Muzan. While trying to save the human he meets Tamayo and Yushirou who were demons but were free from the curse of Muzan. Yushiro takes Kamado and Nezuko to their secret hideout in hopes of finding solution to turn Nezuko back to human.
Tamayo tells Tanjiro Kamado that Nezuko is different and she needs to study her and blood samples of different powerful demons to make elixir capable of turning demons back to humans.
The Trio Meets
While on his way to next mission,Tanjiro Kamado meets Agatsuma Zenitsu, a demon slayer who participated along side Kamado in Final Selection. On their mission to locate next demon, they come across a house where Kamado feels presence of multiple demons. Outside the house were two kids whose elder brother was dragged inside the house by a demon. While fighting inside the house where the internal arrangement of the house was controlled by a Drum Demon, they see Hashibira Inosuke, a battle maniac, fighting another demon.
Inosuke was only there to fight someone more powerful than himself. After defeating the demon and rescuing the boy they were told by Kasugai crow to take rest in the nearby hotel. Inosuke also tagged along Kamado and Zenitsu to the hotel.
Trio’s Encounter with Lower Moon 5
Kamado, Zenitsu and Inosuke were ordered to reach Mount Natagumo for the suspected presence of Lower Moon. Blood Moon’s were the strongest demons handpicked by Muzan to serve him. At Mt. Natagumo they found lower blood moon 5 Rui who shared his power to all the other demons that he deemed as his family. While Kamado Tanjiro was fighting Rui, Inosuke and Zenitsu were fighting other demons.
Even though Tanjiro Kamado was giving his all, he was not able to defeat Rui. When Kamado was on the verge of being killed, Tomioka comes and save him. While on the other side, Shinobu Kochou comes and saves Zenitsu.
The Hashiras
After the battle at Mt. Natagumo, Giyuu was ordered to take Tanjiro and Nezuko to the Master of Demon Slayer Corps Kagaya Ubuyashiki. At the Ubuyashiki Mansion, Kamado meets the Hashiras, the top ranks of the Demon Slayer Rankings.
In presence of the Master and the Hashiras, Tanjiro ‘s determination and Nezuko’s fight against blood-thirst was tested. And it was concluded that Nezuko will not harm humans and will fight againt demons with Kamado. After which they were sent to Shinobu’s Mansion for recuperation.