Nezuko's rankings in the popularity polls are as follows: Nezuko ranked 3rd place in the first popularity poll with 3,319 votes. Nezuko ranked 11th place in the second popularity poll with 5,000 votes.
Nezuko doesn't have a rank. Not all Demons had ranks in Demon Slayer, and since Nezuko was never an ally of Muzan's, she never had a rank in the series.
Master Swordswoman: As a member of the Hashira, Nezuko is one of the most powerful and skilled sword-users in the entire organization. Nezuko is a highly skilled master-level swordswoman, having been trained since birth to be able to defend herself using a katana.
While she might not be as powerful as Muzan himself, her overall strength makes her easily comparable to an Upper rank demon.
Upper Rank 3: Akaza
His abilities make him a formidable foe, and he is feared by both demon slayers and demons alike. Akaza's unique ability is his incredible strength and agility, which allows him to move at lightning speeds and deliver devastating blows to his enemies.
12 Hairo. Kyojuro Rengoku was an admirable Hashira who died a hero's death when he sacrificed his own life to prevent Muzan from killing the three aspiring Demon Slayers who were traveling with him.
4 Muichiro Tokito, The Mist Hashira.
Tanjiro's Current Demon Slayer Rank Is Kanoe
Murata, the Demon Slayer, who was almost digested on Mount Nagumo, is also a Kanoe.
Nezuko's Pyrokinesis aside, her viciously sharp claws slice through flesh like butter, and her powerful kicks can even obliterate an Upper-Moon, so she's far from harmless.
Although Gyutaro might be far stronger, Nezuko would only have to keep up against the demon until sunrise. Her Blood Demon Art is such that it only affects demons, which means there is a very good possibility for her to beat the Upper Moon 6 demons.
And the Wind Hashira, Sanemi Shinazugawa, draws his sword against 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.
The only upper moon that Nezuko can defeat is Daki, it was shown that she was indeed stronger. However, she doesn't stand a chance against the other upper moons. Gyutaro would defeat her quite easily, the others could also do it with not much difficulty.
However, she wasn't immune to the sunlight initially, as she got burned badly at first. So, in conclusion, her coming from a Sun Breathing user's lineage and not relying on human substance are perhaps the reasons for her immunity.
Zenitsu's rankings in the popularity polls are as follows: Zenitsu ranked 2nd place in the first popularity poll with 4,299 votes. Zenitsu ranked 1st place in the second popularity poll with 17,451 votes.
In episode 6 of Demon Slayer season 2, Nezuko entered a berserk state to protect her brother Tanjiro, causing her body to develop into that of an adult. She loses her gag, grows a single horn and gains vine-like patterns across her body.
Refusing to feed on blood initially made Nezuko weaker and gave her a greater gap to overcome when fighting other demons, but her willpower later contributed to huge power boosts during several battles, most notably when she used her awakened form for the first time when fighting against Daki, an Upper Rank demon.
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.
Abnormal Demon Physiology: As the "chosen demon", Nezuko has several unique demonic traits that set her apart from all other demons. Most notably, Nezuko can continuously restore her power without consuming any human blood like any other demon would need to do.
The divine nature of sun breathing: Tanjiro's link to Yoriichi. The flashback also reveals that Yoriichi had a twin brother named Michikatsu Tsugikuni, who became a Demon Slayer but later turned into a demon and became Upper Moon One, Kokushibo.
The number one ranked Kizuki is the terrifying Kokushibo, whose six orange eyes mark him out as one of Demon Slayer's most striking character designs. He also bears a major resemblance to Tanjiro thanks to his red-tipped hair and flame-marked face, although that appears to be a coincidence.
Shinobu Kocho Is the Weakest Hashira
The Insect Hashira, Shinobu's petite frame prevents her from being physically able to decapitate any demon, be it an Upper-Rank or the weakest demon in Japan. At one point or another in the manga, all nine Hashira in Demon Slayer encountered an Upper-Rank.
1. Gyomei Himejima. Gyomei Himejima, the Stone Hashira, is the strongest Hashira in the Demon Slayer corps in terms of strength and swordsmanship. He is the only person who uses spiked flails and an axe instead of standard swords to kill demons.
Sanemi Shinazugawa
His body is covered with battle scars, and he seems to have the most bloodlust out of all the Hashira. He is completely intolerant of demons. All of this aggression seems to leave no room for other emotions, or is the result of repression, seen when he quickly moves on from loved one's deaths.
Sanemi is clearly the least popular Hashira among Demon Slayer fans.