In this article, we will be power scaling Zenitsu Agatsuma, and reaching towards the final arc against Muzan, where he proved himself to be the next Thunder Hashira in Demon Slayer.
Table of Contents
Zenitsu Agatsuma Character Backstory
Zenitsu is one of the main protagonists of Demon Slayer: Kimetsu No Yaiba, along with Inosuke Hashibira, Tanjiro Kamado, and Nezuko Kamado. His backstory isn’t as dark as Tanjiro’s or Inosuke’s unless you count being tricked by girls and spending all your money on them.
Zenitsu always had poor luck with women and never had parents, so the only option he had left to clear his debt was to become a demon Slayer with his Sensei’s help. His sensei’s name was Jigoro Kuwajima who was the “thunder Hashira”. He also had a fellow student called Kaigaku.
As we see in the story, Zenitsu is not a fan of this arrangement, neither is Kaigaku as he admonishes Zenitsu for wasting his sensei’s time. Kaigaku gets angry when Zenitsu refers to his sensei as “Gramps”. Kaigaku makes Zenitsu’s insecurities become inflated as he tries to convince him to leave the dojo and that his skills are inadequate.
Thunder Hashira “Zenitsu Agatsuma”
The first time Tanjiro meets Zenitsu, he has to pull him off a girl who he’s been begging to marry because he thinks he’ll die soon because he’s a Demon Slayer. He is constantly seen as a coward from this point on by Tanjiro and many others, as Zenitsu never wants to fight and just wants to run away.
This is where his story progresses from Arc to Ark, where Zenitsu’s storyline follows through with him getting over his panic attacks and anxiety which stole him from displaying his real enormous strength.
Overall, Zenitsu Agatsuma was stronger and more talented than Kaigaku, even at the dojo, but he felt like he was inadequate due to his lack of confidence. This slowly got built up through working with Tanjiro and the many events that unfolded in the story.
Zenitsu became the Thunder Hashira level also thanks to his two unique powers, one of which being his extremely enhanced sense of hearing. When we first see his abilities shown and described, it’s in the Tsuzumi Mansion Arc. He first hears sounds from very far away, sounds that haven’t even registered for Tanjiro yet.
Using this ability, he is able to discern humans from demons as well, as it is shown when he says that he knew Tanjiro was carrying a demon all along. Zenitsu’s sense of hearing is so overpowered that he can also sense a demon or a person’s strength level. As shown when he noticed immediately that Daiki was a demon and could even tell she was an upper rank.
This sense of hearing also allows him to fight whilst unconscious with his eyes closed as he can sense his surroundings and even what people are thinking.
As mentioned earlier, Zenitsu has two unique types of powers that make him Hashira Level. Zenitsu’s fighting ability asleep is his second power. When Zenitsu is scared enough, he blacks out from fear and his body moves to protect itself.
Now with other people, this might not change much in terms of power. But he was trained by the Thunder Hashira for a long time, so his instincts combined with the training his body was beaten into, turned him into a demon-slaying pro.
Zenitsu’s “Thunder Breathing Style”
Let us now dive into Zenitsu’s thunder breathing style. Zenitsu Agatsuma actually matched his sensei and achieved Hashira level by the end of the series by mastering this breath style. he can only perform the first form of Thunder Breathing out of the six forms. Now, you might think that he is weaker compared to Tanjiro and Inosuke because of this, but you’d think wrong.
Zenitsu may only be able to use the first form of Thunder breathing but he has mastered that form to perfection, even creating extensions of this technique to increase his speed and power. This includes Thunderclap and Flash: Sixfold which he uses to defeat the Spider demon in chapter 34, where he uses the techniques six times in a row to further augment his speed and power.
We now move on to the Rehabilitation Training arc which propelled Zenitsu forward in terms of power, allowing him to close in more towards the level of Thunder Hashira.
In this arc, Zenitsu learns total concentration breathing which all Hashiras use. As Regoku said to Tanjiro, this technique is the first step to reaching Hashira. This technique allowed Zenitsu to use Thunder Breathing to an even greater extent.
After learning Total Concentration Breathing constant, he improved dramatically but his growth doesn’t stop there. He achieves even greater feats in the entertainment district arc. In this arc, he defeats Daki, who even Tanjiro was nearly killed by.
Zenitsu uses two new techniques while fighting against Daki; an upgraded version of the sixfold technique which he now performed eight times in a row! But what’s even more impressive was his second technique called Godspeed which even shocked Daki.
This technique involves him generating an immense amount of power and focusing it on his legs which takes his speed to its maximum potential. He is capable of taking on even Upper-rank demon moons which means he is already nearing Hashira level.
The next arc is where everything changes and Zenitsu Agatsuma becomes Hashira level. The Hashira Training arc is where Tanjiro, Inosuke, and Zenitsu all undergo Hashira training. It is in this arc that Zenitsu learns that his sensei had committed Seppuku after finding out that Kaigaku had transformed into a demon.
Despite having complaints in the earlier part of his training, it is at this point of the story where we see a striking difference in Zenitsu. Zenitsu attains clarity on what he needs to do in order to accomplish his sensei’s will.
Infinity Castle Arc: Zenitsu Vs Kaigaku
Finally, in the Infinity Castle Arc, we get to see a completely different side of Zenitsu. It is in this arc that Zenitsu encounters upper moon 6 who we learn to be Kaigaku, Zenitsu’s sibling apprentice. We see Zenitsu in a completely different light, sensing Kaigaku almost immediately and claiming that he is no longer his senior now.
This is the first fight in the whole series where we see how capable Zenitsu is when he is focused and awake. We get to see Zenitsu’s true power as he is easily able to outpace the upper rank six and cuts him. Kaidaku is shocked, saying that “He moves like a completely different person”.
We then got to see Kaigaku’s insecurity as he shows his anger towards his sensei for saying that he and Zenitsu would both be his successors. Zenitsu apologizes to Kaigaku and Gramps and we get to see the true extent of Zenitsu’s new power.
Zenitsu releases his own seventh form of thunder breathing, killing Kaigaku immediately. This is a much bigger deal by the way than you think. It’s completely unheard of and even among the Hashiras, only a couple have achieved this.
So as Kaigaku crumbles, his insecurities are once again highlighted as he thinks that Zenitsu Agatsuma was favored by his sensei and was the only one taught this technique. Zenitsu quickly explains that he created that technique specifically to become Kaigaku’s equal meaning that at this point in time Zenitsu has already reached a hashira level of power.
Zenitsu versus Demon King “Muzan”
However, by the end of Demon Slayer he even surpassed that level in some ways as there are more feats to Zenitsu’s growth and powers against the demon king himself, Muzan.
Now although it may not seem like Zenitsu versus Muzan shows much of his growth, there are subtle elements scattered. The first being that although he is still very much fatigued and injured from fighting Kaigaku, he can still fight against the king of demons.
We also see his growth with his other techniques; thunderclap and flash and godspeed, as before the Hashira Training Arc, an unconscious Zenitsu remarks that he should not use this technique more than two times. But against Muzan we see him use it multiple times whilst injured.
Zenitsu even uses his seventh form once again and we do have to keep in mind that he’s fighting on par with Hashira despite not even being a marked one nor did he even have the red blade.
So that is it for Zenitsu’s growth into a Hashira level demon slayer by the end of the series. Zenitsu was a force to be reckoned with despite his interesting personality, becoming a demon slayer capable of killing upper ranks and fighting the demon king Muzan himself.