Demon Slayer is a show about swords. Nichirin blades, breathing forms, and colour-coded steel. So why does the demon who steals the whole first act of the movie never carry a blade at all?

He fights barehanded. And he might be the most dangerous fighter in the film.

The demon who refuses a weapon

Akaza holds the rank of Upper Rank Three inside Muzan’s Twelve Kizuki. That makes him one of the four strongest demons in the entire series. Rengoku learns this the hard way in Mugen Train, and Infinity Castle picks the thread back up with a rematch that fans had been waiting years to see animated.

Here is what sets Akaza apart from almost every other threat in the story. He does not use a Blood Demon Art built around some external object or trick. His power grows straight out of his own body. The fists carry it. The stance shapes it. When he throws a strike, the shockwave travels through the air and arrives before you can read it.

Most demons lean on grotesque transformations. Akaza just walks toward you and hits harder than a sword ever could.

Hakuji: the human underneath the demon

The reason Akaza fights the way he does lives in his human past, and Infinity Castle leans hard into that backstory. Before the demon, there was a young man named Hakuji.

Hakuji grew up poor, stealing to buy medicine for a sick father. That desperation shaped him early. He learned to fight because he had to, and he was frighteningly good at it.

A martial arts master named Keizo eventually noticed that raw talent and took him in. The scale of it is hard to overstate. According to the series backstory, once he had mastered Keizo’s style, an eighteen-year-old Hakuji singlehandedly annihilated 67 trained adult kendo masters with his bare fists, and Muzan first assumed a demon had done the killing.

Keizo ran a dojo. He taught Hakuji a hand-to-hand style, gave him a home, and introduced him to his daughter Koyuki, who became Hakuji’s fiancée. For the first time, Hakuji had something worth protecting.

Then it was ripped away. According to the series backstory, a rival dojo that could never beat Hakuji poisoned the well at Keizo’s school during their bitter feud, killing both Keizo and Koyuki. Hakuji lost everything in a single act of cruelty. He slaughtered the men responsible, and Muzan found him in that broken state and turned him into a demon. Much of this comes to us through memory and lore rather than a scene played out moment by moment, so the film reveals it in fragments. Muzan’s transformation erased Hakuji’s conscious memories, but the fighting instinct stayed, and echoes of his human life lingered underneath.

That is the tragedy the movie asks you to sit with. Akaza kept the muscle memory of a man who trained his whole life to protect people, and he spends a century using it to slaughter the swordsmen who try to protect others. His mind lost the details, yet his body never quite let go. He refuses to kill women the entire time he is a demon, an instinct that traces straight back to Koyuki even though he cannot say why. And in his final battle, the memories come rushing back and change everything about how his story ends.

The martial art behind the myth

Akaza’s fighting style is the Soryu Style, taught to him by Keizo during his human years. After his transformation, that human style fused with his demonic shockwaves into the Blood Demon Art known as Destructive Death.

The details reward a second watch. His signature “Compass Needle” technique lets him read an opponent’s movements and adjust mid-fight, which is why skilled swordsmen struggle against him. The animators even wove his lost memories into the visuals. The technique draws on fireworks and a hairpin that Koyuki once wore, small echoes of the life Muzan erased.

Now, a fair word of caution for the real-world martial artists reading this. Soryu is a fictional style invented for the series, so you will not find a dojo teaching it. That said, the principles the show draws on are real, and they explain why an unarmed fighter can menace a room full of blades.

Real striking arts train exactly the things Akaza demonstrates. Reading distance. Closing the gap before a weapon can be brought to bear. Controlling the centre line so the armed opponent cannot line up a clean cut. A trained boxer or a Muay Thai fighter who gets inside the range of a slow, heavy weapon becomes very dangerous very fast, and historical fencing manuals spend real ink on the problem of the disarmed fighter who refuses to stay disarmed.

That is the honest kernel inside the fantasy. Akaza is exaggerated to superhuman levels, but the fear he creates is grounded in something true about how fights actually work.

Sword versus fist: why the show frames it this way

Demon Slayer keeps returning to a single idea. The weapon matters less than the person holding it, or in Akaza’s case, the person who threw it away.

Tanjiro carries a black Nichirin blade and a will that will not break. Akaza carries nothing and a century of grief. The contrast is the point.

When the two finally clash, the film is really asking whether raw strength or human conviction wins, and it answers that question in a way that recontextualises everything Akaza has done.

For collectors and cosplayers, this is also what makes Akaza such a compelling figure to represent. He is the rare Demon Slayer character defined by the absence of a blade, which throws the show’s iconic Nichirin swords into sharp relief. The colours of those blades carry meaning across the series, and understanding that colour language is half the fun of building a display. Our breakdown of what each Nichirin blade colour actually signifies is a good place to start if you want the full picture.

Bringing the Infinity Castle cast to your shelf

Akaza’s rematch shares the screen with the Hashira, and their blades are the ones fans most want to own after seeing the film. If Infinity Castle sent you down the collecting rabbit hole, the glowing versions of these swords are the natural first step.

Our Demon Slayer LED katana collection covers the main cast, from Tanjiro’s black blade to the Hashira weapons that stand against the Upper Moons. These are edge-lit acrylic and bamboo replicas built for display and cosplay rather than sparring, so they light up a room without pretending to be functional steel.

A quick honest note, because it matters. These are cosplay and display pieces. If you are looking for a blade you can actually train with, that is a different category of product entirely, and our guide to battle-ready versus decorative katanas explains exactly where the line sits so you buy the right thing the first time.

The Akaza’s fight that defines the film

Akaza works because he is more than a wall of strength. He is a man who trained to protect, lost everyone, and got weaponised by the worst being in the story. For most of the film his fists carry a grief he cannot even name, until the moment he finally can.

That is why the internet cannot stop talking about him now that Infinity Castle is streaming. The fight is spectacular. The story underneath it is devastating. And the choice to make the franchise’s scariest fighter a barehanded martial artist, in a show obsessed with swords, was never an accident.

Watch it again. This time, notice how his stance never changes, even as everything he buried comes rushing back to him at the end.

Further reading and sources

• Demon Slayer: Kimetsu no Yaiba Infinity Castle on Crunchyroll for the streaming release
• Rotten Tomatoes: Infinity Castle critical reception for the film’s review scores
• Demon Slayer on Wikipedia for franchise background and character detail
• Hashira and their blades explained