In the anime, there are clearly different shades of brown and black (maybe even dark blue). Not sure if it's the slayer's preference or random. I think it's mostly a distinguishing feature for the anime.
On the manga colors and colored artwork from the author, it looks like the uniforms are more similar in color (i.e. black). Color plays a pivotal role in the symbolism of the Demon Slayer Corps uniforms, acting as a visual language that conveys character traits and emotional depth.
For instance, Tanjiro Kamado's uniform, with its deep green and black checkered pattern, reflects his steadfast nature and determination. A demon slayer is supposed to wear a white long-sleeved collared shirt under the uniform, but as evident from the series, the characters wear different outfits to reflect their personalities and worldviews. In many cultures, uniforms serve as a symbol of authority, rank, and belonging.
The same is true in Demon Slayer, where the clothing worn by the Hashiras tells a lot about their role in society and their unique abilities. The Demon Slayer Corps is a military-like organization, and uniforms are vital for distinguishing between ranks and roles. Colors in the demon slayer uniform are more than mere aesthetics-they convey rank and personality traits.
Did you know that Tanjiro's green-checkered haori signifies his steadfastness and dedication? [Demon Slayer] A thorough look at the 14 uniform types of the Demon Slayer Corps. What color is Tanjiro coat? After becoming a Demon Slayer, Tanjiro wears the standard Demon Slayer uniform, a dark-brown gakuran jacket, a white belt, baggy chocho zubon pants that extend into tabi socks, a pair of zōri with red straps, and bands of white cloth wrapped tightly around his calves resembling kyahan, all beneath his signature What color red is Tanjiro's hair? Tanjiro's hair. Speaking with my friends, I found that many criticize the black uniform of the Demon Slayers Corps, because they resemble too much the Japanese school uniforms.
However, after a little research of the Taisho period, I found that it's the opposite: the Japanese school uniforms copied the army uniform of the Taisho period. Tanjiro Kamado-Demon Slayer color palette created by alex2022 that consists #7c3a43,#58c29e,#2e2723,#5a3536,#f9d4af colors. The Demon Slayer Uniform is a distinctive outfit worn by members of the Demon Slayer Corps from the popular Kimetsu no Yaiba series.
Carefully crafted by uniformed ravens, these uniforms are made of a unique, durable material that is highly resistant to cutting and burning to serve the Demon Slayers in their tireless battle against demons. The uniforms are muted black, with a white haori.