Away from his fears and anxieties, a sleeping Zenitsu can unleash his mighty thunder breathing skills which allow him to move at lightning speed with his Nichirin Blade. His incredible abilities lay dormant underneath his flighty exterior, and sleeping lets him showcase them.
But Zenitsu is not just powerful in his unconscious state. His real power shows when he is aware and awake, he was able to outmatch the new upper rank six demon, Kaigaku. At this point Zenitsu has manifested his speed and power, and he was also able to keep up with the Demon King, Muzan, even when weakened.
Tanjiro Is Strong, and Stronger than Zenitsu as he uses Sun Breathing.
Hence, Zenitsu is stronger than Inosuke in Demon Slayer.
Exploring Zenitsu's fighting abilities in Demon Slayer
Zenitsu has perfected the first form only and is seen performing it only when he's unconscious. But the manga shows that he can fight without fainting or going unconscious.
Demon Slayers are known for their strength and bravery in battle, but not Zenitsu. Despite his cowardice, he's one of the strongest in the series.
Thunder Clap and Flash—Godspeed is the most powerful of Zenitsu's derivations of the Thunder Breathing first-form technique.
After Muzan was defeated, all the demons he created also perished immediately, so there was no point of a Demon Slayer corps anymore. As a result, Zenitsu did not get to become a Hashira even after becoming strong enough to bie one. Demon Slayer is one of the most popular anime series going on right now.
But, comparing the two characters in their best forms, Zenitsu might be just a tad bit faster owing to his Godspeed move.
slow ?! , Deku was able to dodge and hit in a split second. And yet he is clearly faster than Zenitsu .
Sun Breathing has the second highest number of known techniques of all the breathing styles. It has twelve forms that can all be combined into an extremely powerful thirteenth form. It is second only to Moon Breathing which has sixteen techniques, employed by the Upper Rank One demon Kokushibo.
Thunder Breathing is one such technique that Zenitsu has used to great effect in the series. Of course, Zenitsu is only the master of the first form, but it goes without saying that the other techniques of Thunder Breathing will also be awe-inspiring to witness in Demon Slayer.
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.
Hinokami Kagura, also known as Sun Breathing, is easily one of the strongest Breathing Styles in the series by a wide margin. It's the Breathing Style that served as the base for every other style in the series, which is no mean feat.
1 Sun Breathing
It is a legendary breathing style that mimics the sun itself and incorporates that into the user's swordsmanship. Against the Demons, this is known to be the most effective breathing style as it is extremely versatile.
The reason for this is pretty simple. Zenitsu wasn't able to master the other 5 forms. He never wanted to learn any breathing techniques. or fighting techniques, nor he wanted to join the Demon Slayer Corps.
Tengen Uzui
This Breathing Technique gives him echolocation and other advanced hearing abilities. Even though he is large and muscular, and uses that to his advantage, his fighting style relies more on aesthetics and flashiness. He is the fastest Hashira, and the second physically strongest.
Zenitsu was even able to exert himself for around half an hour during the fight against Muzan, even being able to surpass his limit of only being able to use his Thunderclap and Flash: Godspeed technique twice a day before his legs gave out.
8 Shinobu Kocho, The Insect Hashira
That being said, she's arguably the weakest Hashira when it comes to pure strength.
Zenitsu trained under the former Thunder Hashira, Jigoro Kuwajima. Under Jigoro's strict training, Zenitsu only mastered the first form of Thunder Breathing. Although he often tried to run away from Jigoro, he highly respected his mentor and viewed him as a parental figure.
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.
2) Tanjiro Kamado
With Sun Breathing, which is regarded as the paramount of all Breathing Styles, Zenitsu will have a hard time subduing Tanjiro and will be defeated by the latter in no time.
With his master gone, Zenitsu can no longer learn the remaining five forms. Therefore, during his fight with Kaigaku, an Upper Moon Six, he created a 7th form.
3) Zenitsu Agatsuma
If he could, Rengoku would win simply because Zenitsu cannot perform Godspeed more than twice. Since Zenitsu only knows the first form, Rengoku would know what to expect and accordingly counter his moves, taking him down in the end.