On June 18, Demon Slayer aired its third season finale to such immense viewership that Crunchyroll’s servers temporarily crashed. Anime fans have followed along with Tanjiro and Nezuko’s adventures for four years now, witnessing Tanjiro develop from a young fragile boy into a lethal and disciplined Demon Slayer. His sister has evolved herself along the way, managing to harness her demon abilities to fight the forces of evil, resisting the urge to devour any human she encounters.
During Tanjiro’s journey to becoming one of the greatest Demon Slayers to exist, he is often assisted by other members of the Demon Slayer Corps, as well as certain characters whose purpose is to serve Slayers and hone their skills. One such character is Hotaru Haganezuka, the swordsmith who forged Tanjiro’s sword, which was assigned the rare shade of black when wielded. In the fight against Lower Rank Rive, Rui, Tanjiro breaks his blade, envisioning Hotaru’s anger and disappointment.
When we first meet Hotaru and for most of the anime, he wears a Hyottoko mask, as do all the swordsmiths. Masks have been explored numerous times throughout the series, starting with Sabito during Tanjiro’s training to prepare for the Final Selection. When instructed to slice cleanly through a large boulder in order to progress, Tanjiro hallucinates Sabito and Makomo, fighting the former until one day overpowering him and slashing his fox mask clean down the middle.
But that begs the question as to why swordsmiths wear these Hyottoko masks in the first place. These swordsmiths don’t wear masks with special spells to protect them from harm in the battlefield. Instead, they choose to conceal their identity because they are an important asset to the Demon Slayer Corps and therefore a giant target for demons. At least if swordsmiths hide their faces, demons can’t easily identify them in a crowd of people, should they need to reveal their true appearance and blend in.
The blades crafted by swordsmiths are made from a fictional ore called the “Scarlet Ore,” which can be found on Sunlight Mountain, a place constantly exposed to sunlight. Therefore, the ore itself has absorbed the UV energy necessary to effectively kill a demon, and holds it even after the ore is forged.
There’s a crucial reason as to why the Swordsmith Village’s location is kept hidden from all, even Demon Slayers. If the demons decided to mount an attack to wipe out all swordsmiths, then no Nichirin blades would be made, therefore increasing a demon’s chances of survival and making sunlight the only viable method of killing them.
All episodes of Demon Slayer are available to stream on Crunchyroll, Hulu, and FunimationNow.
