Nichirin Blades are special blades used by and made specifically for the Demon Slaying 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.
The blue Nichirin Blade symbolizes water and Giyu Tomioka, the Pillar of Water of the Demon Slayer Corps, wields a blue blade that he uses with his Breath of Water style, making him one of the most formidable among the Pillars.
Tomioka's fighting style is very water-like. He moves in a fluid, almost effortless motions to make short work of demons. He killed both the Father Spider Demon and Rui, the Lower Moon Five demon, with one fluid motion in each kill.
Blade: The blade of the sword has been constructed from stainless steel and comes slightly sharpened and has a black,and silver edge finish.
Scabbard: The scabbard is constructed of wood with black and brass accessories
Handle: The handle of the sword is a black faux leather liner with white wrap.