Nichirin sword colours: what each blade reveals

A masked swordsmith hands a new blade to its owner and holds his breath. The demon slayer draws it. The steel, grey at first, slowly takes on a tint: blue, red, green, or black. The swordsmith smiles, or starts screaming. In Demon Slayer, the colour of a sword is anything but decorative: it is a verdict, and each character receives it in their own way.

Here is where these colours come from, what each one reveals, who bears them, and why black is so worrying. Our page on Nichirin swords, colours, forging and meaning presents the weapon as a whole.

Why do Nichirin swords change colour?

Nichirin swords are forged from scarlet iron sand and ore, mined from a mountain where the sun shines all year round. This metal absorbs daylight, and that is what allows it to kill a demon when it cuts off its head. The name itself combines the characters for sun and ring.

A new blade is a neutral grey. It only takes on its colour in the hand of its owner, the first time they draw it, and only if they have already reached a certain level. The tint then reveals the breathing style that suits them best. In the Corps, they are in fact known as the colour-changing swords.

This moment is a ritual. The swordsmith comes in person, attends the first drawing and discovers at the same time as his client what the blade is going to become. Our article on the village swordsmiths tells of these masked craftsmen.

It all begins just after the Final Selection, on Mount Fujikasane. Each new recruit chooses the ore for their future blade themselves, from among several pieces. The village swordsmith takes it away, works it in his family’s style, then comes back a few days later with the finished sword. The demon slayer therefore only discovers its colour once the blade is in their hands, in front of the person who forged it.

Sword colours, breathing style by breathing style

Each breathing style has its colour. The five basic styles give the clearest colours, the derived styles more unexpected shades. The table brings them together with their best-known bearers.

The rule has only one real exception in style: Zenitsu’s blade does not bear a solid colour but a lightning pattern. Our page on all the Demon Slayer breathing styles explains each style.

The blue of Water

Blue is the colour you come across most often in the series. Water Breathing is one of the most widespread in the Corps, because it adapts to almost every body and almost every opponent. Sakonji Urokodaki, the former Water Hashira, taught it to generations of pupils, including Giyu Tomioka, Sabito and Makomo.

Giyu’s blade is a deep blue, and so is that of Murata, the ordinary demon slayer met on Mount Natagumo. Same colour, same breathing style, two opposite destinies: one is a Hashira, the other remains a simple soldier throughout the war. The colour tells the breathing style, not the talent. Tanjiro learned Water Breathing from Urokodaki, and yet his blade turned black: the colour was already announcing that this style did not quite suit him, which he would feel himself on Mount Natagumo. Our article on Water Breathing and its eleven forms details this style.

Our 104 cm replica features Giyu’s blade, which goes from black to light blue towards the tip, with its red and gold hexagonal guard. It is filed in the complete Giyu Tomioka collection.

The red of Flame

The Rengoku family has produced Flame Hashira for generations, and their blades are red. Kyojuro’s burns orange-red, extended by a flame-shaped guard, handed down from father to son. In the Mugen Train film, every form of Flame Breathing turns this blade into a blaze.

The red of Flame should not be confused with crimson red, the state any blade can reach by heating to a very high temperature. The first is a colour from birth, the second a combat state. Senjuro, Kyojuro’s younger brother, also received a sword, but the blade never changed colour in his hands: he understood that he would not be a demon slayer like his elder brother. Our portrait of Kyojuro Rengoku, the Flame Hashira tells his story.

The green of Wind and the grey of Stone

Sanemi Shinazugawa, the Wind Hashira, carries a green blade, as rough as his temperament. Wind Breathing is violent, made of whirlwinds and gusts, and its colour recalls leaves torn away by the storm.

Gyomei Himejima, the Stone Hashira, does not wield a katana but an axe and a spiked flail, linked by a chain. His weapons are grey, the colour of stone, and weigh so much that only he can lift them. Our article on the Hashira’s weapons presents these made-to-measure weapons.

For a Sanemi cosplay, our green-bladed LED katana lights up a bright green, in 80 or 100 cm, with a bamboo and acrylic blade. It is in the Demon Slayer LED katanas collection.

The yellow of Thunder and its lightning bolts

Thunder Breathing gives a yellow blade. Zenitsu Agatsuma’s is special in that it is not a solid colour: a lightning pattern runs along its entire length, as if the weapon kept the trace of the single strike its bearer repeats to perfection. His master, Jigoro Kuwajima, a former Thunder Hashira, passed this breathing style on to him.

The pattern fits the character. Zenitsu masters only one form, the first, but he unleashes it at a speed no one can match. His blade shows exactly that: a flash of lightning, and nothing else. Our article on Thunder Breathing tells of this style.

Our 104 cm replica features this black blade streaked with yellow-green lightning, with its yellow flower guard. It is filed in the complete Zenitsu Agatsuma collection.

The colours of the derived breathing styles

The derived breathing styles have subtler colours. Flower, practised by Kanae Kocho and then by Kanao Tsuyuri, gives a pale pink blade. Shinobu’s Insect, a lavender blue blade, as thin as a needle. Mitsuri Kanroji’s Love, a deep pink, on a blade as supple as a whip. Obanai Iguro’s Serpent, a lavender, wavy blade.

Muichiro Tokito’s Mist gives a white blade, like a fog. Tengen Uzui’s Sound, amber-coloured blades, mounted on large cleavers linked by a chain. Inosuke’s Beast, an indigo grey, on two blades he chips himself against stones. Each colour says something about the character who carries it.

The colour does not follow the family of the breathing style, either. Flower descends from Water, and its blades are pink, not blue. Love comes from Flame, and its blade leans towards pink rather than red. It really is the bearer who colours the weapon, not the school they come from. Our page on the Demon Slayer Hashira presents each of these fighters.

Black, the colour that worries

When Tanjiro draws his sword for the first time, the blade turns black. His swordsmith, Hotaru Haganezuka, who was hoping for a brilliant red, flies into a black rage and starts shaking the boy, accusing him of ruining his work. In the Corps, black blades have a bad reputation: it is said that their bearers do not go far, often because they die before understanding what is special about their sword.

The truth is only revealed much later. Black is the colour of Sun Breathing, the first of all breathing styles, the style of Yoriichi Tsugikuni. This breathing style had almost disappeared, and the few demon slayers who had a black blade did not know how to use it. Tanjiro practises it without knowing, through his family’s Dance of the Fire God. Our page Tanjiro Kamado, everything about the hero traces that path.

Our article on Tanjiro’s black sword tells of this blade in detail. Our 104 cm replica, all in black with its wheel guard pierced with slots, is in the complete Tanjiro Kamado collection.

The purple of the Moon

One blade escapes every rule: that of Kokushibo, Upper Moon One. A former demon slayer turned demon, he practises Moon Breathing, and his weapon is no longer a forged sword but a blade born of his own flesh, a dark purple, covered in eyes that open along its entire length. It lengthens and branches out at will.

It is the only weapon in the series that is both a demon slayer’s sword and a demon’s organ. Our article on Moon Breathing presents this style, and our portrait of Kokushibo, Upper Moon One tells his story.

The crimson red blade, a combat state

All these colours have one thing in common: they can all give way to crimson red. Brought to a very high temperature, a Nichirin blade turns red and slows down demons’ regeneration. Nezuko achieves this effect with her Exploding Blood, and marked demon slayers with a strong enough grip or by clashing two blades together.

This red is not a colour from birth but a weapon of last resort, decisive against the Upper Moons. Four centuries earlier, Yoriichi Tsugikuni needed none of this: his blade turned red as soon as he gripped it. Our article on the crimson red blade details the three ways of obtaining it.

Choosing a replica in your character’s colour

For a cosplay, the colour of the blade is what the eye notices first, even before the guard. A blue blade calls for Giyu, a green one Sanemi, a black one Tanjiro, a yellow one streaked with lightning Zenitsu. Choose the colour before the model: it is what will make your character recognisable in a convention photo. Our 104 cm replicas feature these colours on a bamboo blade, and our LED katanas light the blade up in the character’s colour.

A katana at the belt completes any demon slayer cosplay, and it is often the accessory that makes the character recognisable at first glance. Our article on which Demon Slayer katana to choose compares replicas, LED and LED mist katanas, and the Demon Slayer katanas collection brings them all together.