Nezuko, on the other hand, never was under Muzan's curse, it would seem. Instead, she used her will to protect her brother and other humans to fight off the curse. This is probably why Nezuko sleeps instead of eating humans. This also means her strength as a demon is based on her will to protect rather than feed.
During the Demon Slayer season 3 finale's depiction of Tamayo analyzing Nezuko's blood, it's shown that Nezuko's blood has blue elements to it, and since the Blue Spider Lily has the power to cure Muzan of his weakness to sunlight, the anime could be revealing that Nezuko's immunity comes from the Blue Spider Lily at ...
This wasn't explained in the anime, but Nezuko was able to remove the curse of Muzan on her own way, just like what Tamayo (Demon doctor) did. This was when Tanjirou and co. arrived on the Butterfly estate after the Hashira meeting. As for how she removed the curse, it wasn't explained.
Well, the answer is simple. Kagaya's illness isn't caused by poison. It's a curse that was placed on his family. Muzan is actually one of his ancestors, and when he became a demon, it put a curse on the Ubuyashiki family.
Muzan Kibutsuji may have tried to kill Nezuko by exploding her after injecting a lot of his blood into her veins. But she was somehow able to survive with that much of Muzan's blood, that's what possibly made her a powerful demon.
Secondly, Muzan would probably… eat Nezuko and Tanjiro in the hopes of obtaining their sun-resistance abilities, and also since he wouldn't be able to convince them to become demons to work under him. This would allow him to become the ultimate demon.
Since Nezuko is from a Sun Breathing lineage, she can survive in daylight. After the final battle against Hantengu concludes, she can step into daylight, and many theories are available about the phenomenon. One of the theories is that her abstinence from consuming human blood is what saved her.
In conclusion, Nezuko cannot beat Akaza in Demon Slayer. In terms of power, physical abilities, regeneration rate and overall combat ability, Akaza is far superior compared to Nezuko.
1 Muzan (Demon Slayer)
Without that antidote, it would have been impossible to kill him. So despite all her strength and humanity, Nezuko would have easily lost to Muzan.
Nezuko is at least stronger than Daki, meaning that if Muzan could bring her back under his control, she would certainly qualify for the most prestigious title a demon can hold: a member of the Twelve Kizuki. Thanks to Nezuko's remarkable strength, she would have to be an Upper-Moon.
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.
It is revealed that Muzan's true fear of dying and immense desire to live and survive was due to him being born "dead," where his heart would constantly stop in his mother's womb and was assumed stillborn until he fought to breathe before his cremation.
Moreover, while she was asleep, Urokodaki performed a unique hypnotism on Nezuko, making her believe that all humans are her family and she must not hurt them in any way. With her immense fondness for humanity, Nezuko broke out of Muzan's control, becoming free to do anything at her will.
As Muzan begins to disintegrate, he becomes so overwhelmed with emotion that he decides to pass on his dream to Tanjiro. After realizing his abilities to use the Sun Breathing, Muzan decides that Tanjiro is capable of surviving to make his dream come true, and become the King of Demons.
However, Muzan was desperate from the beginning, and it reflected in his dying moments as well. Muzan refused to die and when he was finally about to breathe his last, he transferred all the blood to Tanjiro in the hope that he would become the successor and carry out his will.
Origin. The first demon that is said to have existed was Muzan Kibutsuji. The one who turned him into a demon was a generous doctor from the Heian Period, who wanted to save Muzan from death since, at the time, he was diagnosed with a disease which would kill him before he turned twenty.
Nezuko becomes much stronger throughout Demon Slayer. She's stronger or even as strong as an upper moon.
1 Yoriichi Tsugikuni (Demon Slayer)
Yoriichi's mastery of the Sun Breathing technique, combined with his incredible speed and agility, made him a formidable opponent for Muzan.
Giyu is one of the legendary Hashira, and he's brought down demons far more powerful than Nezuko. With his level of skill and impressive agility, he'd easily defeat Tanjiro's little sister.
So if Nezuko ate a human. and continued to do so over time, her power could rival that of Upper Moon one or 2, and here's why. One, if you're a manga reader, you know, in her base, Nezuko conquers the sun. And 2, her blood demon art can nullify.
This willpower is also what helps Nezuko truly utilize her Awakened form, to fight more efficiently. While she might not be as powerful as Muzan himself, her overall strength makes her easily comparable to an Upper rank demon.
Tanjiro used Thunder Breathing during their battle with the fourth Upper Moon, Hantengu, to cut some distance between him and the latter. This moment came out of nowhere and caused a lot of hype online.
Muzan's Recipe For Immortality
He wanted to be able to walk in the sunlight and live forever. In order to gain this, he needed two things: the Blue Spider Lily and the body of a demon who could withstand the sun.
Unlike other demons who survive on blood, Nezuko never really needs it, and she doesn't even consume human food either. Moreover, Nezuko has never shown any signs of undernourishment as she is always ready to assist her brother with her overwhelming strength and deadly Blood Demon Art.