Superhuman Hearing: Zenitsu has always had enhanced hearing, being able to hear what others can't. He is able to hear a faint difference that is normally indetectable to humans in the sound of a moving human and a moving demon. His hearing gives him extra awareness for danger.
His immense stamina and will, makes him a powerful opponent as he is able to go long periods of time in battle without giving up. Just like his comrade Tanjiro, Zenitsu also refuses to give up in the heat of a battle and was able to battle with extremely stronger demons such as Kaigaku and Muzan.
Thunder Clap and Flash—Godspeed is the most powerful of Zenitsu's derivations of the Thunder Breathing first-form technique.
Overall, Zenitsu is an extraordinary powerful Demon Slayer capable of singlehandedly bringing down an Upper Rank, which said to be able to overpower 5 Hashira, in 10 minutes, albeit he would have beheaded Kaigaku in a heartbeat if it wasn't for his feelings of melancholy and pity.
Zenitsu is an incredibly powerful Demon Slayer, but he's always in fear. His nerves calm down when he's asleep, so that's when he awakens his “powers”. MANGA SPOILER AHEAD!!!
Zenitsu Agatsuma is a part of the Demon Slayer Corps who the previous Thunder Hashira trained. Zenitsu is a skilled and able member of the organization but gets easily scared when facing demons. But as the series continues, we watch him grow as he eventually overcomes his fear of demons and fights them head-on.
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.
slow ?! , Deku was able to dodge and hit in a split second. And yet he is clearly faster than Zenitsu .
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.
But, comparing the two characters in their best forms, Zenitsu might be just a tad bit faster owing to his Godspeed move.
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.
Nezuko Kamado
Zenitsu also protects Nezuko multiple times when she is in danger, evident during Zenitsu's first meeting with Inosuke Hashibira and the battle against Enmu in the train. Eventually Zenitsu and Nezuko would marry and start a family as evidenced by their descendants.
1) Tanjiro Kamado
Although he and Zenitsu along with Inosuke, started training together, he excelled both in the matters of strength and swordsmanship. Tanjiro with his Sun Breathing is more powerful than Zenitsu.
How fast is Zenitsu?? I mean it's difficult to tell, but at least 750 mph since he can break the sound barrier.
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.
A known cultivator of Thunder Breathing in the Demon Slayer Corps is the former Thunder Hashira, Jigoro Kuwajima.
1 Tanjiro Kamado
Demon Slayer's protagonist is also, unsurprisingly, the anime's most popular character by quite a wide margin. Tanjiro is kind to his friends, but he also doesn't hesitate to put them into place for their poor behavior, particularly when it comes to Inosuke and Zenitsu.
Gyomei Himejima: The Blind Stone Hashira with Unmatched Strength. Among the Hashira, Gyomei Himejima stands out as the Stone Hashira, with unmatched raw physical strength.
Godspeed ( 神 しん 速 そく , Shinsoku?) - An extension of the Thunderclap and Flash technique created by Zenitsu. The user performs Thunderclap and Flash while greatly augmenting the speed of the technique.
Before she's able to do so, however, Zenitsu comes rushing in with his Godlike Speed technique that sees him zipping right towards her. Unlike the first speedy time he had used this against her previously in the season, this technique is a lot more damaging.
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.
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.
8 Shinobu Kocho, The Insect Hashira
That being said, she's arguably the weakest Hashira when it comes to pure strength.