Webto answer in short, tanjiro’s sword is black mostly because he is a user of multiple breathing techniques including sun breathing, and also to signify that he will go. Webdefying the curse of black blades shows tanjiro‘s inner strength and character triumphing over destiny. The black color has thematic ties to tanjiro‘s. Webfans have wondered why tanjiro is the only user with a black blade in demon slayer. Later, in the manga, it is revealed that yoriichi too wielded a black. Webtanjiro’s sword turns black after coming in contact with his hand (and internal energy) due to his dormant knowledge of the strongest breathing style, sun. Webwhy swordsmen with black katanas suck. When’s tanjiro’s blade turns black it’s mentioned by present company that a black sword is considered an. When demon slayer protagonist. Webwe see this firsthand when tanjiro (natsuki hanae/zach aguilar) gets his new sword at the tail end of season 1, only for it to turn an ominous black. Webwhen 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. Webtanjiro is using his masters blue blade. We don't get an explanation for the others but it's likely they all know about final selection through some connection that likely has a blade.
