So, what is the mystery behind the sword and the doll? Webwhile tanjiro is embarrassed about ruining such a sacred antique, he and kotetsu discover that yoriichi type zero has been literally housing the secret of a. Webdemon slayer season 3 episode 2 review: Webthe sword’s mysterious origins. During an intense training session with the yoriichi type zero, tanjiro accidentally breaks part of the doll, revealing an ancient sword that had been hidden inside for centuries. This weapon, forged over 300 years ago, predates most of the demon slayers swords currently used by demon slayers. Webyoriichi pioneered sun breathing and forged the iconic red nichirin blade, establishing his legendary status in the demon slayer corps for centuries to come. Webthe sword fitted into yoriichi type zero belonged to the legendary swordsman yoriichi tsukiguni from the sengoku era. He was a genius when it came to. Although rusted, it survived for centuries inside the.