These conditions allow the ore to be infused with sunlight, which is the only significant weakness that demons face. It’s a rite of passage and part of a Demon Slayer’s training to acquire the ore that’s used to construct their weapon. Once forged, these Nichirin blade swords constantly absorb sunlight, which allows them to be essentially the only tool that’s practically able to kill demons. Nichirin blades are therefore the primary weapon of the Demon Slayer Corps and an essential tool.
Additionally, an even stronger version of this weapon, Crimson Red Nichirin blades, can be achieved by raising the sword’s temperature to extreme levels, striking two Nichirin blades together in the right manner, or the application of the right form of intense Blood Demon Art. A Crimson Red Nichirin sword is even more efficient because the heat allows demons to be destroyed on a molecular level, which means that amputations or wounds from this blade won’t heal like the standard kind.
Why Do The Swords Take On Different Colors?
Nichirin blades are also referred to as “Color Changing Swords” and the reason for this is that the blades adopt a distinct color when they’re first drawn by their Demon Slayer owner. Granted, this color transformation isn’t mandatory and the Demon Slayer needs to already be at a certain level of skill to trigger the process in the first place. This makes the act even more special and an easy marker for when a Demon Slayer begins to increase in strength.
In terms of the colorful transformation itself, it’s supposed to be emblematic of the personality, technique, and general energy that lies within each Demon Slayer. For instance, someone with a fiery and aggressive resolve would likely see their sword turn orange or red, whereas a Demon Slayer that’s full of love might receive a pink blade. These unique colors make the swords operate as an extension of the Demon Slayer and their values.
Another aspect of individuality that’s present with each sword is the unique handguard that protects the wielder from its blade. These handguards don’t possess any special powers and are more in the control of the sword’s owner, but they’re still a fun element that translates to the Demon Slayer equivalent of flair. Tanjiro’s handguard is a subtle black ring with a wheel aesthetic, but others like Shinobu and Mitsuri’s flower and clover-shaped handguards are much more creative and reflect their respective Hashira arts.