After a Demon attack kills almost her entire family, Nezuko is turned into a Demon by the orchestrator of said attack, Muzan Kibutsuji.
Ultimately, Nezuko survives and finally turns into a human after being stuck as a demon for so long. Despite turning into a human, she's one of the prime reasons why Tanjiro could defeat Muzan, even after almost being turned into a demon himself. The manga comes to a conclusion after the fight with Muzan.
Fans later questioned the reason for letting Nezuko live. Fans believed this could have been a strategic move from Muzan. The theory states that Muzan wanted to create a demon that developed an immunity to the sun. Upon doing so, he would consume the aforementioned demon and become invincible.
To sum things up, Tanjiro died fighting Muzan and was revived within seconds due to the transfer of blood from the Demon King to Tanjiro. He turns into a Demon and Kanao injects a certain medicine made from Wisteria flowers that turns him back to a human.
A few years later, after Tanjiro had joined the Demon Slayer Corps, he encountered Muzan Kibutsuji while visiting the city of Asakusa. It was there that Tanjiro confirmed by Muzan's scent that he was the demon who'd massacred the Kamado family.
Zenitsu also protects Nezuko multiple times when she is in danger, evident during Zenitsu's first meeting with Inosuke Hashibira and the battle against Enmu in the train. Eventually Zenitsu and Nezuko would marry and start a family as evidenced by their descendants.
The explosion, which was enhanced by spike traps, manages to injure Muzan. Before he is able to regenerate fully, Tamayo appears and uses her Blood Demon Art to keep him in place, while using a drug that can turn him into human. Using this opportunity, Gyomei Himejima appears and destroys Muzan's head.
Tanjiro and Nezuko return to their family home, accompanied by Zenitsu and Inosuke. Tanjiro marries fellow demon slayer Kanao Tsuyuri while Nezuko marries Zenitsu. In a modern-day epilogue, the descendants and reincarnations of the Corps members enjoy a peaceful life free of demons.
The black blade represents the Sun and is surrounded by prejudice and misconceptions, as historically every demon slayer who held it lived a short life. This could mean that Tanjirou is destined to break the pattern and set a new legend for black Nichirin blades in the Demon Slayer universe.
Tanjuro Kamado was the name of Tanjiro Kamado's father. He passed away before the event of the main story of the Demon Slayer. It is not mentioned how long Tanjuro had passed before the story, but in several flashback scenes, we can see him interacting with a younger Tanjiro.
Curse of Kibutsuji
This curse besotted any who partake of Muzan's blood must be careful. The curse prevents Muzan's name from being spoken aloud, and any who do will meet a horrible demise. One demon, Susamaru, faced this reality when battling Tamayo.
Demon Curse: Muzan places a curse on all demons that have assimilated his blood. If any demon divulges his last name "Kibutsuji" out loud, the curse activates, which causes their bodies to stop regenerating and allowing Muzan's cells inside the demon to take over and kill them, regardless of their original intent.
In the world of Demon Slayer, demons live off eating humans, leading to the massive slaughter of innocent lives. The point of putting a muzzle on Nezuko is to prevent her from attacking and subsequently eating humans. However, it comes with the side effect of severely limiting her ability to speak.
Nezuko survives without eating humans because unlike other demons who need human flesh to get back their energy , nezuko gets back her energy sleeping . As we see in the anime she sleeps in the box Tanjiro carries on his back .
Zenitsu Agatsuma
She apparently views Zenitsu as a "weird dandelion" and did not initially seem to reciprocate his feelings. Although the two are rarely seen interacting together, Zenitsu treats her with affection and care.
Later it is revealed that he married fellow slayer Kanao Tsuyuri, In the Modern World, Tanjiro and Kano had Great-great-great grandsons named: Sumihiko Kamado and Kanata Kamado.
Black. Toho Co., Ltd. Black is the most mysterious color of all the blades, and is held by the main character, Tanjiro. It is a rare blade and represents the sun; it also holds a theory that the demon slayers who own this sword are not to live a long life.
When Haganezuka sees Tanjiro's reddish hair, he becomes hopeful that he will get to see a bright red Nichirin sword. However, once Tanjiro unsheathes his weapon, the blade turns a dark black, to the concern of Urokodaki and the anger of Haganezuka.
Even 400 years later, Muzan's fear of Yoriichi remained fully intact, as simply laying eyes on Tanjiro's hanafuda earrings caused him to recall their clash.
It is confirmed in the Volume 23 extras that Inosuke and Aoi did eventually end up together and that they have two great-grandsons, one of which is Aoba.
Tanjiro Is Strong, and Stronger than Zenitsu as he uses Sun Breathing.
Unfortunately, the answer to this question would be, no, he did not. Zenitsu, along with Tanjiro and Inosuke got way stronger than average corps members with training. In fact, he became one of the very few to even invent a new form of Thunder Breathing. However, his dream of becoming a Hashira was never realized.
Tanjiro decapitates Akaza with the Hinokami Kagura: Setting Sun Transformation. Akaza was bewildered, wondering how Tanjiro did not have any fighting spirit, comparing this feeling to fighting against a plant. He acknowledges that Tanjiro surpassed his speed.
The Water Hashira, Giyu, survived the "Infinity Castle" arc after fighting at Tanjiro's side against both Akaza and Muzan.
The divine nature of Sun-Breathing is the reason Tanjiro Kamado bears such a striking resemblance to Yoriichi, even though the two are not related.