Nichirin Sword

Nichirin Blades (日 (にち) 輪 (りん) 刀 (とう) , Nichirin tou^?) are special blades used by and made specifically for the Demon Slayer Corps to slay Demons.They are forged from a unique ore that constantly absorbs sunlight, one of the only major weaknesses of Demons. Therefore, decapitation by Nichirin Blade is one of the only ways a human can kill a Demon, the other being the use of a Wisteria-poison coated weapon.

Nichirin Blades take on a distinct color when first drawn by its owner, which is why they are also referred to as "The Color Changing Swords". However, the holder is required to have a certain amount of skill, or the blade will not change color.

Forging Process

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.

Demon Slayer recruits choose their own ore after successfully passing the Final Selection. The ore will then be used by a swordsmith of the Swordsmith Village during the forging process, and the swordsmith will personally bring the weapon to the Demon Slayer.

Handguards

Each nichirin Blade contains a handguard, or tsuba, that protects the swordsman from cutting themselves. It is located where the handle and the blade meet and can come in a varitey of colors and shapes. However based on his appearances in the series, Inosuke Hashibira's nichirin blades do not have handguards

Swordsman	Description of Handguard	Picture
Tanjiro Kamado*	Black ring connected to its core by lines.
Zenitsu Agatsuma	Circular shaped with 4 slight indentions, the center has a silver tone with small triangles and has a golden border.	File:Zenitsu's Tsuba E12.png
Giyu Tomioka	Hexagonal shaped with a bronze core and with an overlapping fuschia border. Tomioka's second blade obtained during the fight against Muzan has a handguard resembling a whirlpool
Shinobu Kocho	Flower shaped with 4 petals; The petal has an aqua colored core with an orange border
Kyojuro Rengoku	Shaped like a flame with a red core and golden border
Mitsuri Kanroji	Shaped like a 4 leaf clover; The leaves have a pink core with a golden border
Muichiro Tokito	Rectangular shaped with hollowed rectangles at each corner.
Sanemi Shinazugawa	Abstract shape with 8 points with an overlapping pattern; Each  plate has a forest green core with a silver border.
Obanai Iguro	Circular shape engraved with a snake

*Tanjiro began using Kyojuro's handguard as of Chapter 129.

Blade Colors

Kyojuro explaining Breath Styles' associated colors.

Nichirin Blades change color depending upon the user, making each blade unique. They can be of many colors. Zenitsu Agatsuma's blade is unique in that its coloration does not form as a solid band but instead as a lightning motif down the length of the blade. The reason for this patterning is unknown.

Each color is said to impart certain properties to the blade. The properties of black Nichirin Blades are not well understood, causing them to be considered a bad omen that the Demon Slayer will not go far (due to dying before much can be learned about the blade). By raising the temperature of the blade with a strong grip, Demon Slayers are able to change their Nichirin Blade's color to red, which prevents demons from regenerating damage done by the blade. Clashing a Nichirin Blade with other Nichirin Blades will also turn them red and give them the same qualities.

Symbolism	Colors	No.	Known users
Sun	Black	2	Tanjiro Kamado Yoriichi Tsugikuni
Sound	Amber	1	Tengen Uzui
Water	Blue	2	Giyu Tomioka Sakonji Urokodaki
Stone	Gray	1	Gyomei Himejima
Wind	Green	1	Sanemi Shinazugawa
Beast	Indigo-Gray	1	Inosuke Hashibira
Serpent	Lavender	1	Obanai Iguro
Insect	Lavender-Blue	1	Shinobu Kocho
Flower	Light Pink	2	Kanao Tsuyuri Kanae Kocho
Love	Pink	1	Mitsuri Kanroji
Moon	Purple	1	Kokushibo
Flame	Red	1	Kyojuro Rengoku
Mist	White	1	Muichiro Tokito
Thunder	Yellow	1	Zenitsu Agatsuma