Standard Nichirin Katana: As a Demon Slayer, Yoriichi carries around a standard sized and shaped Nichirin katana that is deep black in color, but changes bright red during combat.
Black. Toho Co., Ltd. Black is the most mysterious color of all the blades, and is held by the main character, Tanjiro. It is a rare blade and represents the sun; it also holds a theory that the demon slayers who own this sword are not to live a long life.
Yoriichi Tsugikuni's bright red Nichirin sword is the most potent out of all Demon Slayers, being able to burn on a cellular level and leave scars that even the Demon King himself can't heal even after centuries.
It was Yoriichi's sword, he found it inside Yoriichi Type Zero doll when he destroy the head. And then hotaru took the sword to fix it. Tanjiro also use Kyojuro's tsuba in this sword.
Tanjiro Kamado wields a black Nichirin blade, but the symbolism of such a sword is unknown. Black blades are seen as a rarity, as demon slayers who wield them are doomed to die young. No wielder of a black sword has ever become a Hashira, either.
The Nichirin sword that Mistsuri uses is a pink whip-like sword that fits perfectly with her overall appeal and style. Her sword is said to be one of the fastest because of how incredibly quick they are to the point that not even Tengen Uzui's swords could reach speeds that fast.
Black Nichirin Blade
The most mysterious sword color from Demon Slayer is the one Kanjiro wields. The black blade represents the Sun and is surrounded by prejudice and misconceptions, as historically every demon slayer who held it lived a short life.
Standard Nichirin Katana: As a Demon Slayer, Yoriichi carries around a standard sized and shaped Nichirin katana that is deep black in color, but changes bright red during combat.
This color was first discovered by Yoriichi Tsugikuni when he became a Demon Slayer due to his Sun Breathing. In fact, it is a category of Yoriichi's gifted powers and abilities, which is meant to hamper the regeneration of Demons.
But if we are talking about the human form, then it's a big fat NO, because Tanjiro has just mastered the Sun Breathing whereas Yoriichi is the inventor of it, also he's way more powerful and holds an unfathomable battle intellect, larger than any Demon Slayer in history, so in conclusion, no one is remotely close to ...
The nichirin sword Yoriichi uses is unique, changing from black to crimson red. Once it changes color, Yoriichi can use his weapon to burn any demon and even suppress their healing ability.
Why was Yoriichi sword black? Later, in the manga, it is revealed that Yoriichi too wielded a black Nichirin blade. The only two users who could perform techniques from the breath of the sun had black Nichirin blades. Certain fans also believed that the color black was there for thematic purposes.
When Tanjiro first got his Nichirin Sword on Demon Slayer, and it changed color to match the personality of its user like all Nichirin weapons do, many fans were surprised that Tanjiro's katana turned black.
Inosuke operates with two blades that are a cool indigo-grey in color, in response to Inosuke's beastly nature. Breath of the Beast is certainly appropriate for Inosuke and it meshes with the sleek nature of indigo-grey.
After being cut by Tanjiro, the head from Yoriichi Type Zero tumbles down only to reveal a 300 year-old katana hidden within its body.
Tanjiro's ancestor was a good friend of Yoriichi and arguably was one of his only true friends. Therefore Yoriichi gave the earrings as a gift, and since then they have been passed down the generations until they reached Tanjiro.
The divine nature of Sun-Breathing is the reason Tanjiro Kamado bears such a striking resemblance to Yoriichi, even though the two are not related.
When Haganezuka sees Tanjiro's reddish hair, he becomes hopeful that he will get to see a bright red Nichirin sword. However, once Tanjiro unsheathes his weapon, the blade turns a dark black, to the concern of Urokodaki and the anger of Haganezuka.
As the master of the Sun Breathing Style, Yoriichi was able to destroy 1500 of 1800 pieces of Muzan in a series of attacks. While unable to fully destroy Muzan before the last 300 pieces escaped to regenerate, Yoriichi came closer than anyone else until Tanjiro and friends succeeded.
Tanjiro certainly did a lot of good with his Water Breathing techniques, but his ability to use Sun Breathing both gives him an edge in battle and allows him to stand out among the incredibly powerful Hashira he fights alongside.
Nichirin Blades are forged with Scarlet Crimson Iron Sand and Scarlet Crimson Ore, both of which are found on high mountains like the Sunlight Mountain, which is perpetually bathed in sunlight all throughout the year.
These blades aren't ordinary iron or steel, they're actually crafted from a fictional ore called the "Scarlet Ore" that can be found on Sunlight mountain.
Being one of the strongest Hashira, Sanemi's sword matches his appearance. His sword is very durable and lasts throughout the series. It had no problem piercing through the box that Nezuko is held in. He fought against Kokushibo during the final arc of the manga.