Tōshū

Toshu was a swordsmith who was supposedly forced by Ryūjin, a humanoid dragon, into forging the demon sword Dakki from his own scales. He first appeared in manga chapter 386, hiding from Ryujin's murderous search for him. After Inuyasha's group chased the dragon away, Toshu told them about how he met Ryujin a year ago while travelling through the remains of a battlefield, and that Ryujin demanded that Toshu forge a sword for him using his dragon scales. To remind him of the deal, he gave Toshu a mark on the right eye. Fearing for his own life, Toshu attempted to forge Dakki, with many failed attempts. Inuyasha and his group protected and defended him when Ryujin comes for the sword. While battling with Inuyasha, Ryujin attempted to persuade Toshu to give up the sword; Toshu instead told Inuyasha about the dragon's weaknesses; namely, parts of his body were unprotected by scales, as he'd ripped them out to use in making powerful weapons. When Ryujin was defeated, Toshu quickly and ruthlessly plunged Dakki into the heavily-injured dragon, allowing it to consume Ryujin's youki and become a complete yōkai sword. It was then revealed that he intended to make the most powerful sword in the world, and that he was the one who offered to forge a sword for Ryujin. Attempting to take Tessaiga's power, he attacked Inuyasha and managed to make a steadily widening crack in Tessaiga. His ambition proved to be his undoing, however, for his body deteriorated and fused with his sword. Finally, he met his demise when Dakki, afraid of breaking, instead let Toshu's entire body take the damage, thus killing him.