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.
She was ranked in 3rd place in the first Demon Slayer character popularity poll with 3,319 votes. IGN regarded Nezuko as one of the series's most popular characters and noted how her design elaborates the way she sees humans as good people as a result of hypnosis.
While her regenerative abilities were slower due to her refusal to feed on humans, the ability was drastically boosted when Nezuko entered her “Awakened” Demonic form. During her fight with Daki, the Upper Rank demon admitted that her regenerative power rivaled that of Upper Rank demons, and was superior to her own.
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.
Nezuko's most significant trait, however, is her immense growth, which is likely due to a combination of the amount of blood she received from Muzan and her willpower. To conclude, Nezuko is a formidable powerhouse within the anime and is probably one of the strongest main characters in the series.
Given that she survived the Final Selection, she has excellent combat abilities. But Nezuko single-handedly overwhelmed Daki, showing just how strong she is as a demon. Therefore, it can be assumed that Nezuko would be able to beat Aoi if the two engaged in combat.
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.
1/10 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.
Overall Abilities: As a Hashira of the Demon Slayer Corps, Nezuko is a very powerful and skilled swordswoman and combatant.
Apart from Tanjiro, the show centers on his younger sister Nezuko Kamado, turned into a demon by Muzan Kibutsuji. Demons are incapable of walking out in broad daylight because the sunlight will burn them into the ashes. However, Nezuko has immunity against the sun, so she was given the name “The Chosen Demon”.
Nezuko Obliterated Daki with Blind Rage.
This means that there is a way for Nezuko to beat any of the Upper Moon 6 demons: Daki, Gyutaro, or Kaigaku. To do so, Nezuko would have to fight the demons outdoors and prolong the fight long enough for the powerful demons to be exposed to sunlight.
Second of all, upper moon 5 isn't even weak at all. Nezuko can't even solo gyutaro and daki combined, when daki was stated to be “literally” holding back gyutaro. Idk where you got the fact that she can solo UM 6. She might be able to kill a lower moon at her manga ending level, but no way an upper moon.
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.
Which Hashira can beat Nezuko? The Wind Hashira is one of the strongest Hashiras in the Demon Slayer series. He played a significant role in defeating Kokushibo and was able to inflict damage on Muzan. Sanemi's sheer power and speed will be able to overwhelm Nezuko even in her final form.
Nezuko sets Tengen on fire. Everyone momentarily pauses when Nezuko suddenly appears next to Tengen, they proceed to stare at her as she raises her hand and grabs his arm, before setting him on fire. His wives look on in horror until Suma comically pulls Nezuko away, saying that its too soon to cremate him.
Pyrokinesis: Nezuko's Blood Demon Art allows her to generate and manipulate special demonic flames created from her blood that are pinkish in color. Nezuko can do this by igniting her blood or creating it from thin air.
Tanjiro's rage at Daki's massacre maxed out his Sun-Breathing power, while seeing her brother so wounded forced Nezuko to remember her family's slaughter, causing her to lose control. It turns out the eldest Kamado children are known for their tempers, and Daki managed to enrage them both.
Another way sakura wins is that she literally beats her up so hard that nezuko begins to flee since demons also have a sense of fear (a lot of demons fear hashira) just because there's no way sakura can kill her doesn't mean there's no way sakura can defeat her. Sakura wins from a K.O or nezuko flees.
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.
Sound Hashira
He is the fastest Hashira, and the second physically strongest. Obviously, then, Tengen Uzui is rather proud. He is demanding, fussy, boastful, and prone to selfishness. But he is also ultimately kind and caring, with great love for his three wives as well as the other Hashira.
3/10 Can't Beat: Nezuko
Her strength and speed when she's embracing her new demon abilities are pretty impressive, and she'd likely give Zenitsu a run for his money if they were to fight.
When it comes to pure strength, Shinobu Kocho is the weakest Hashira in Demon Slayer. She doesn't even have enough strength to decapitate a demon's head and she makes up for it by injecting poison into the demons.
Physical ability. Nezuko would be far stronger than Tanjiro in the base form in terms of pure physical abilities. But Tanjiro gained superhuman strength and speed owing to the activation of the Demon Slayer Mark. Comparing the two in these forms, Nezuko might still outperform in terms of speed and strength.
There is no doubt that Nezuko is faster and stronger than the base form of Tanjiro. However, he can activate his Demon Slayer Mark and happens to be a user of the Breath of the Sun. This gives him an edge because it is one of the series' strongest and most efficient breathing techniques.