WARNING: HEAVY DEMON SLAYER MANGA SPOILERS BELOW
With the Demon Slayer anime adaptation’s Entertainment District arc, the series is at the forefront of contemporary animanga news. Recent episodes have thrust the main cast of Zenitsu, Tanjiro, and Inosuke to the front of fans’ minds.
As a result, they have been curious about Zenitsu Agatsuma’s backstory and abilities. While his barebones heritage has been covered, fans are still interested in the young Thunder Breathing Demon Slayer Corps member’s potential and background.
Demon Slayer fans curious as to Zenitsu’s backstory and abilities as he, Tanjiro, and Inosuke star in anime’s current arc
Zenitsu Agatsuma backstory
Zenitsu’s story in Demon Slayer, unfortunately, starts with him taking on a debt for a woman he’s smitten with. Unfortunately, she ends up running away with someone else, thus sticking Zenitsu with the debt and no girl. Zenitsu is then taken in by Jigoro Kuwajima (who also takes care of his debt).
Jigoro is a former Thunder Hashira and takes Zenitsu in to train him in the ways of Thunder Breathing. The two develop a fantastic bond, similar to a grandfather and grandson, hence why Zenitsu calls Jigoro Gramps.
There was also another student called Kaigaku, who would often chastise Zenitsu for calling Jigoro Gramps and his other informal behavior. Kaigaku even seems resentful towards Zenitsu, criticizing him constantly for being a crybaby, among other things.
One day, when Zenitsu was hiding in a tree from Jigoro (who he thought would train him to death), he was struck by lightning. Zenitsu survived, but his hair changed from black to the trademark yellow seen throughout the series.
This is the final piece to set up Kaigaku and Zenitsu as literary foils, now finally different in everything from attitude to appearance. Although Zenitsu also feels negatively towards Kaigaku, he still respects his fellow student, unlike Kaigaku.
From here, Zenitsu’s story unfolds from his first appearance on Demon Slayer. He passes Final Selection, receives his Kasugai Sparrow (instead of a Crow), and then meets Tanjiro Kamado while begging a woman’s hand for marriage. Zenitsu would then focus his rage on Tanjiro and ask Tanjiro to protect him until he gets married.
Tanjiro and Zenitsu then arrive at the Tsuzumi Drum Demon’s house, where Zenitsu is able to hear a drumbeat when neither Tanjiro nor the children can. This demonstrates his excellent sense of hearing, an ability that will be discussed later.
Upon entering the house, Tanjiro and Zenitsu are separated, leading to another ability of Zenitsu’s being divulged in Demon Slayer.
From Zenitsu’s first appearances, we can tell he is someone who’s constantly terrified, desires marriage, and genuinely feels he won’t live long as a Demon Slayer. While Zenitsu is by and large a coward, he does have his moments of bravery and good intentions.
A perfect example is him protecting Nezuko’s box from Inosuke Hashibira, despite knowing there’s a demon inside because he knows it’s vital to Tanjiro.
Although he survived the Final Selection, Zenitsu’s clearly not mentally ready to be a proper Demon Slayer. Yet his powers and abilities give him the skills needed when he’s in the right mindset.
This is also demonstrated in the Tsuzumi Drum House, where Zenitsu passes out from fear and beheads a demon in one stroke in the process.
While he obviously has plenty more experiences throughout the story, there’s one incredibly relevant encounter to his backstory.
At the end of the series, Zenitsu finds out that Kaigaku became a Demon thanks to Kokushibo. It’s here we discover Jigoro had killed himself because of Kaigaku’s turning and the shame it brought.
Kaigaku mocks Zenitsu as their fight begins, constantly teasing him for only being able to do one technique of Thunder Breathing. Further portraying them as literary foils, Zenitsu reveals that the one technique he can do is the only one Kaigaku can’t.
At the end of their battle, Zenitsu displays a brand new, never-before-seen Thunder Breathing technique he created. It kills Kaigaku, and thus, Zenitsu redeems his tragically late master.
Powers and abilities
Some of Zenitsu’s biggest inherent strengths are his exceptional sense of hearing and his ability to sense the emotions of living things through his hearing. When meeting Tanjiro, he remarks that he sounds so full of kindness.
He’s also able to tell that a Demon is inside Tanjiro’s box through his hearing, which he still chooses to defend for Tanjiro’s sake.
As far as powers and abilities, fans also learn through a flashback that Zenitsu can only perform Thunder Breathing’s first technique. It is something that makes Zenitsu very insecure, even with Jigoro telling him if you can only do one thing, then do it superbly.
Zenitsu certainly takes this to heart, as he’s able to stack multiple Thunderclap and Flashes on top of each other and perform them in quick succession.
When facing Kaigaku in their final battle, it’s revealed that Zenitsu created his own seventh form for the Thunder Breathing Style. Dubbed the Honoikazuchi no Kami, Zenitsu uses it to defeat Kaigaku and finally fight on equal ground with him, which is what he made the technique for.
It’s an interesting depth to their foils that Kaigaku relied on Muzan’s blood to become stronger, whereas Zenitsu created his own technique.
It’s also worth noting that creating a new technique is only seen one other time in the series, when done by Giyu Tomioka. Tomioka is also a Water Hashira, putting Zenitsu as comparable to a Hashira in this regard.
Although Zenitsu’s lack of mastery over the other forms would throw a wrench in this comparison, Zenitsu is still somewhat of a Hashira level Demon Slayer.
Beyond his swordplay and Breathing Style, Zenitsu also has a fantastic battle IQ and immense stamina and endurance. Furthermore, his speed and reflexes are incredibly close to a demon’s level, or potentially even a Hashira in Demon Slayer.
Although known for being somewhat of a scaredy-cat, Zenitsu is able to hang with the best of the Demon Slayers in nearly any situation. He is also one of two characters to create a new Form for their Breathing Style, something only a Hashira is otherwise shown to do.
Zenitsu’s backstory is also incredibly relevant to him as a character, especially as he foils with Kaigaku. The way their stories collide and resolve in the final chapters of the series is brilliantly done, giving both appropriate and well-written closures.