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.
Nezuko doesn't stand a chance against the Upper Moon 3
Nezuko is undoubtedly a strong demon in Demon Slayer and she proved her strength repeatedly. One situation that really displayed her true potential was the fight against Daki. She underwent a transformation and thoroughly overwhelmed the Upper Moon 6 demon.
While she might not be as powerful as Muzan himself, her overall strength makes her easily comparable to an Upper rank demon.
Nezuko can be ranked at the level of an Upper Moon 5 since she is considerably weaker than the likes of Kokushibo and Doma.
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.
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.
If Nezuko were to taste blood, it's likely that she would lose control completely, forcing Tanjiro and other demon slayers to kill her. So the bamboo gag really protects Nezuko as well as the other humans the slayers may encounter on their journey.
Muzan, the King of Demons, is the strongest and also the primal demon in the world of Demon Slayer. Consuming his blood is enough to turn you into a powerful demon. He can control all the demons in existence, with only people with strong willpower like Nezuko being an exception.
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.
How Doma became the worst demon in Demon Slayer. Almost every creature possesses emotions, be it anguish, sorrow, happiness, or even fear. However, in the case of Doma, he doesn't feel a thing. During his childhood, his mother stabbed his father to death for cheating on her and, later on, took her own life.
Nezuko's Sunlight Immunity in Demon Slayer is Tied to the Blue Spider Lily. Nezuko having eaten the Blue Spider Lily at some point could explain her immunity to sunlight, and Demon Slayer: Kimetsu no Yaiba has already worked to justify that.
Since Nezuko isn't a part of the Twelve Kizuki, she doesn't get a demon rank. She does however have her own demon blood art, as well super-fast reflexes and the ability to grow and shrink in size.
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.
Since he didn't know anything about the Blue Spider Lily medicine, he needed others to find the plant for him by happenstance. This is the general reason why Muzan turned Nezuko into a demon. More specifically though, was the fact that Nezuko was of Kamado blood.
Her most prominent traits is her extraordinary growth rate possibly due to the high amount of blood she received from Muzan Kibutsuji when he turned Nezuko into a demon and the fact that she doesn't need to consume human blood to survive.
With the emergence of demons in the modern age, Nezuko returned to active duty as the Sun Hashira and reassembled the Demon Slayer Corps, assuming the leadership position and moving Kiriya Ubuyashiki to the Ubuyashiki-Kamado complex, in order to keep him safe from harm.
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.
If Zenitsu fought Akaza with his plethora of Thunder Breathing techniques, the latter wouldn't have the time to regenerate his limbs.
Nezuko isn't like other demons, which is how she was given the name 'The Chosen Demon'. The reason behind this is because unlike other demons, she can actually walk in the sunlight without getting burned. It is shown in the manga chapter 130, She has walked in the sun.
3 Rapid Regeneration
She was even able to reattach her own severed head in the blink of an eye which is even more impressive as no other Upper Rank was able to perform such a feat yet in the anime. Daki herself was surprised at Nezuko's immense regeneration.
With this in mind, if Nezuko had also been murdered by Muzan, Tanjiro would have no reason to be empathetic toward demons. Her transformation gave him a perspective of both demons and humans, but without Nezuko becoming a demon he would have no reason to take their feelings into account.
as a human, Nezuko had long, wavy, jet black hair. but since being transformed into a demon, small, vibrant, fiery streaks have appeared.
Nezuko is the daughter of Tanjuro Kamado and Tanjiro's younger sister who is turned into a demon Despite Muzan Kibutsuji assumption that he has killed them all in his attempt to sire a sun-resistant demon, Nezuko survives as a demon with her mind mostly gone.