Fans of Demon Slayer are familiar with the Nichirin sword, and most probably know that these swords come in a variety of colors. What they’re less likely to know, however, is exactly what these colors mean, and what the colors say about their wielders.
In Demon Slayer, a Nichirin sword is a special type of katana that absorbs sunlight and is crafted from materials known as Scarlet Crimson Iron Sand and Scarlet Ore, fictitious substances that give the swords their color-changing ability. It’s said that when the true wielder of a Nichirin sword picks it up for the first time, its blade will change to a particular color that’s suited to the individual. For Tanjiro, that meant that his blade turned black, a rare color that the swordsmith who delivered it wasn’t too familiar with. Black blades were said to be unlucky, but that was a superstition that arose from their rarity.
Nichirin Come in Many Colors, but Black is Strongest
A Nichirin sword’s color actually has some connection to what Breathing Style that demon slayer is most adept at. Blades associated with Water Breathing typically change to a blue color, for example, while that of a user of the Flame Breathing technique would turn red. Continuing down the list of elements, Thunder Breathing is yellow, Stone Breathing is gray, and Wind Breathing is green. These five cover the overwhelming majority of Nichirin blades known to exist since these are the most common styles.
However, there are some characters who have specialized even further, such as Shinobu Kocho, the Insect Hashira, whose personal style is technically a subset of Water Breathing. As such, her sword is a light purple or lavender in color–still close to water’s blue, but distinct, just like her style. Tanjiro’s black-colored blade is secretly associated with the Sun Breathing technique, the progenitor style from which all Breathing Styles are derived.
Nichirin Swords Vary in More Ways than Color
Nichirin swords don’t have to be solid in color, either. Several characters have blades that bear unique patterns or markings on them, which seem to also be considered part of the color-changing property. For example, Zenitsu’s sword doesn’t turn yellow in Demon Slayer, but instead sports a branching lightning bolt-esque marking that takes on that yellow coloration instead. The exact reason for this is never made clear, but since the colors still align, it’s not a major problem.
Several characters are also in possession of weapons that don’t qualify as katanas, particularly among Demon Slayer’s powerful Hashira. Mitsuri Kanroji wields a pink, whip-like blade, for instance, while Shinobu’s is more like a rapier, to better suit her poison-based fighting. Serpentine blades, massive paired cleavers, and an axe on a chain are also used by some demon slayers. Genya even wields a shotgun that fires “Nichirin shells,” bullets made of the same material as the swords themselves.
The color of one’s Nichirin sword can have a massive impact on their career in Demon Slayer, and it’s always interesting to see what color blade each character ends up with.