Tōtōsai

"I, Tōtōsai, forged the Tessaiga from a fang your father gave me. In the world of sword-wielding demons, I am famous among those who know and among those who don't know, I'm not."

- Tōtōsai

is an elderly blacksmith Yōkai who forged Tessaiga and Tenseiga from the fangs of his old friend, The Inu no Taisho. As Inuyasha grows stronger and Sesshomaru grows more compassionate, they become more capable of mastering their respective swords, which Totosai strengthens accordingly. He spends most of his time at his forge inside a volcano, but sometimes travels elsewhere on a flying three-eyed ox named Mō-Mō.

Totosai often appears to be a cowardly, absent-minded old man, but he is strong enough to pause an attack from Sesshomaru long enough to allow Inuyasha to get away; he can breathe fire and his giant forge hammer can open large fire pits in the ground. At the end of the series, he continues his role as a blacksmith as seen when giving Kohaku a new weapon.

Inu no Taisho
An old friend of the Great Dog Demon, Totosai turned one of the fangs belonging to his friend into the mighty Tessaiga at his request, After the blade gained the power of the Meido Zangetsuha from Shishinki, Totosai complied with Inu no Tiasho's desire to seperate and seal the technique into a new blade born of Tessaiga, the Tenseiga. When Inu no Taisho died, Totosai mourned his death along with Myoga and Saiya.

Myoga
Totosai is also an old friend to Myoga the flea demon. He often teases Myoga about running away from danger, but allows him to stay with him when he's not out-and-about, looking for Inuyasha.

Inu no Taisho's sons
Totosai would often meet with Inuyasha when he experienced a problem with Tessaiga. However, he grealy dislikes how Inuyasha treats the blade like a wooden club and badly nicks it. He has a great lack of confidence in the half-demon's ability to understand the will of Tessaiga, but none the less assists when he deems it neccassary. As Inuyasha is not that bright, Totosai often has to explain a great deal about Tessaiga and what tasks Inuyasha needs to complete in order to master new abilites.

later in the series he forged tokijin one of the most powerfull (if not the most powerfull) swords in the series

Unlike Inuyasha, Sesshomaru causes Totosai great fear (he fears for his life the very second he sees him), forcing him to go on he runs when he is asked to make a sword that rivaled Tessaiga. However, he knows that the Bakusaiga exists in Sesshomaru and does his best to help him overcome the blade's test to see if Sesshomaru is worthy of it. Beforehand, he reforged Tenseiga, unlocking the Meido Zangetsua for the blade of the underworld because Sesshomaru had felt concern for another who died. He makes a sheath for Bakusaiga once it is created, making it match the blade's handle.

kaijinbo
Under Tōtōsai's wing, Kaijinbō crafted weapons housing great and sinister powers. Disgusted by the results of his works, Tōtōsai banished him. Even then, he continued his work in spite of him.

later in the series he forged tokijin one of the most powerfull (if not the most powerfull) swords in the series and the naginata of kenkon, much to the disliking of totosai.

Creations

 * Tessaiga
 * Tenseiga
 * An unnamed weapon for Kohaku
 * A sheath for the Bakusaiga
 * A knife with a smily for Saiya.