Tōtōsai

is an elderly swordsmith yōkai specializing in the demonic, who forged Tessaiga and Tenseiga from the fangs of his old friend, the Inu no Taishō. 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.

History
Tōtōsai created Tessaiga for the Inu no Taishō, at his request, granting the blade the power to steal abilities from those it fells. When the Inu no Taishō defeated Shishinki and gained the deadly Meidō Zangetsuha technique, Tōtōsai complied with his wish of separating the technique from the blade and into another part of Tessaiga; this blade could bring back a dead person once and send all the undead back to the afterlife. Tōtōsai considered calling this new weapon the "Coffin Cheater", but the Inu no Taishō preferred to call the blade "Tenseiga".

He also learned that the Inu no Taishō believed Sesshōmaru would come to manifest his own weapon, the Bakusaiga; however, it would test him to see if he was worthy of it.

Tenseiga and Tessaiga
Tōtōsai is commissioned by Sesshōmaru to create a sword that rivaled Tessaiga; however, he instead flees with Myōga, who informs him Inuyasha had once used the Kaze no Kizu. Believing that Inuyasha could protect him from Sesshōmaru, Tōtōsai met with him, testing Tessaiga to see what had become of it. To his sorrow, he found the blade was full of nicks and wondered if Inuyasha had been using it to chop down trees. After revealing his identity, Tōtōsai saw Sesshōmaru had come after him; he had the brothers fight briefly before creating a ring of fire to allow him and Inuyasha's group to get to safety. After sharpening Tessaiga for Inuyasha, Tōtōsai took off to go back home; however, Sesshōmaru returned, this time with a dragon's claw. Tōtōsai watched in amazement as Inuyasha invoked the Wind Scar willingly and Tenseiga teleported Sesshōmaru to safety. Leaving for home this time, Tōtōsai realized "that cunning old hound" made it so fighting for Tessaiga would be pointless.

Inuyasha later brings the broken Tessaiga to him for repairs. Tōtōsai toke one of Inuyasha's fangs to use as a bridge to bond the pieces back together. After three days, Tōtōsai went to give Tessaiga back to Inuyasha, encountering his old apprentice Kaijinbō; he had been possessed by the evil blade Tōkijin, created from the fangs of Goshinki, the demon whose fangs broke Tessaiga to begin with. When Kaijinbō was destroyed by Tōkijin's evil, he explained to Inuyasha that Tessaiga had become heavy because the fang he used to repair it was Inuyasha's which had not yet caught up to the Inu no Taishō in power. When Sesshōmaru came to claim Tōkijin, Tōtōsai provided another distraction by creating a wall of fire.

After Inuyasha had gone through numerous transformation due to his demon blood, Tōtōsai received a visit from him and saw that his human heart was suffering from this; Inuyasha feared going after even Kagome if he lost control again. Tōtōsai sent him to the Valley of Ryūkotsusei, to slay the demon that the Inu no Taishō put under seal. Tōtōsai later met the rest of Inuyasha's group met up with him and Tōtōsai explained the task he sent Inuyasha to do. However, when Ryūkotsusei was awoken by Naraku breaking the seal on him, Tōtōsai blamed Inuyasha. He and the others watched in amazement as Inuyasha fought against his demon blood and successfully used the Bakuryūha to kill Ryūkotsusei. Tōtōsai was even more amazed to learn Inuyasha thought the Ultimate Technique of Tessaiga was a new trick he put in it.

Lending Assistance
Inuyasha later came to him, seeking a way to break Naraku's barrier. However, Tōtōsai accidentally tricked him into preparing a bath for him. Myōga later told him that Inuyasha would most likely kill him for the trickery. Revealing the ruse, Tōtōsai was whacked on the head; however, as a reward for the hard work, Tōtōsai was going to reveal killing the barrier guardian of the bat demons would grant Tessaiga the power to break barriers; he sent Myōga to pass this on to Inuyasha.

After Sesshōmaru broke Tōkijin in battle with Mōryōmaru, Tōtōsai was summoned by Tenseiga; he also noticed that the Tōkijin was no more. Tōtōsai demanded Tenseiga back, saying that since Sesshōmaru's heart now had what it was lacking, he was ready to handle the Meidō Zangetsuha. Revealing what the technique did, Tōtōsai left Sesshōmaru to perfect the Path to the Underworld it created.

Inuyasha later came to him, asking about a blade called Dakki. Tōtōsai warned Inuyasha that losing to the true blade (the broken one that Inuyasha was having him examine was a fake) would reduce Tessaiga to a useless rusty blade (most likely unable to suppress the demon blood in him ever again). When Inuyasha succeeded in destroying Dakki and gaining its power to steal demonic energy, Tōtōsai was sought out again; he revealed Tessaiga heated up when drawing in demonic energy to warn Inuyasha to let go of it before a backlash of energy could kill him. Tōtōsai sent Inuyasha to train with the Great Holy Demon Spirit to learn how to detect demon vortexes.

Knowing Sesshōmaru would eventually find out the truth about Tenseiga and the Meidō Zangetsuha, Tōtōsai prepared to move, only to find Sesshōmaru sending part of his home to the Underworld with a Meidō. Tōtōsai revealed that it was true he created Tenseiga to house the Meidō Zangetsuha; he was then surprised Sesshōmaru had figured out that since the technique had now been mastered, Tessaiga could now reabsorb it lost power. Creating a ring of fire to block Sesshōmaru from sending a Meidō at him, Tōtōsai told Sesshōmaru that since his thoughts are clouded, he cannot learn what the Inu no Taishō's long-term plan was. Tōtōsai then barely avoided the Meidō that swallowed most of his home.

When Tenseiga and Tessaiga clashed, Tōtōsai appeared before Inuyasha's group and Jaken and Rin, using Mō-Mō as a movie projector to show them the battle between the blades. Tōtōsai became amazed that Inuyasha realized Tessaiga's will so fast; however, he bluntly said there was no way for Inuyasha and Sesshōmaru to escape the Path to the Underworld. However, he was proven wrong when Tenseiga (which had been broken on Tessaiga, but repaired itself) guided Inuyasha into using the Meidō to lead him and Sesshōmaru back to the World of the Living.

Tōtōsai later sensed that Bakusaiga would soon appear and took off, arriving at the battle between Sesshōmaru and Magatsuhi. He watched as Bakusaiga appeared in Sesshōmaru's new left arm. He explained the Inu no Taishō's belief and why Bakusaiga hadn't appeared until then. He created a sheath for the deadly blade and explained to Inuyasha that Magatsuhi could only be cut down by Tenseiga.

As everyone fought inside Naraku's body, Tōtōsai watched on with Myōga, explaining that Meidō Zangetsuha would soon evolve to match Inuyasha's fighting style. The Meidō soon did, turning into blades that severed objects just like a blade would and sucking them into the afterlife.

Later life
Tōtōsai remains at his volcanic home, allowing Myōga to stay with him. Flying on Mō-Mō, Tōtōsai meets up with Kohaku, whose on Kirara, giving a new weapon - "it's a bit heavy." Before parting ways, Tōtōsai asked Kohaku if he visited Sango from time to time, only to hear he finds it too crowded at her house.

Physical description
Tōtōsai takes the appearance of a scranky old man. He has huge eyes that are always seen wide open (unless expressing emotions); he has black irises. Balding, Tōtōsai has what remains of his hair tied in a topknot. He has a thin beard at the end of his chin with a mustache that's (seemingly) shaved in the middle. He wears a green hoari with black horizontal strikes on it, with matching hakama. Like Rin and Inuyasha, Tōtōsai goes barefoot.

Personality
Tōtōsai could be described as eccentric or simply insane/senile. At some times, Tōtōsai acts like he's suffering from Alzheimer's by claiming that he does not remember things that have happened to avoid being punished. He loves to poke fun at others, even though with Inuyasha, he usually ends up with a whack to the head. When it comes to the blades he crafts, Tōtōsai is protective of them, even wanted to end Tessaiga's suffering at Inuyasha's hands by melting it into cutlery (during his first meeting with Inuyasha). He cannot stand crafting blade through or for evil methods, banishing his apprentice Kaijinbō for killing ten innocent children to make a demonic sword. He is greatly concerned for his life, knowing that Sesshōmaru and other demons will kill him if he doesn't comply with their demands.

Powers & Abilities

 * Master Swordsmith: Tōtōsai has created numerous blades in his time, being able to craft them with any ability that is within his power to grant. He can lock/unlock powers in the blades, such as in Tenseiga's case. Tōtōsai has also been seen repairing Miroku's staff and Hiraikotsu (after Kaijinbō cut it in half).
 * Communication with Swords: Tōtōsai has been seen to hear the "voices" of blades, saying Tessaiga was singing a sad song because of how Inuyasha wielded it. He can also be summoned by them, such as when Tenseiga summoned him to Sesshōmaru due a change in the daiyōkai's heart. When Bakusaiga was about to appear, Tōtōsai heard numerous pieces of metal in his workshop vibrating, hinting he can communicate with blades he knows about.
 * Pyrokenesis: Tōtōsai is able to breath fire to help him with forging blades, and make it erupt from the ground with a strike of his hammer. Not very powerful on its own, it does prove useful with dealing with the living dead. It also proves useful in creating a diversion if he needs to escape from someone or something.
 * Enhanced Eyesight: At any time he chooses, Tōtōsai can see the battles his blades are in. However, he has only shown this ability once in "Episode 15 (FA)", where he is able to use Mō-Mō like a movie projector to show others the battle between Tenseiga and Tessaiga.

Relationships
An old friend of the Inu no Taishō, Tōtōsai turned one of the fangs belonging to his friend into the mighty Tessaiga at his request, After the blade gained the power of the Meidō Zangetsuha from Shishinki, Tōtōsai complied with the Inu no Taishō's desire to separate and seal the technique into a new blade born of Tessaiga, the Tenseiga. When the Inu no Taishō died, Tōtōsai mourned his death along with Myōga and Saya.
 * Inu no Taishō

Tōtōsai is also an old friend to Myōga the flea demon. He often teases Myōga about running away from danger, but allows him to stay with him when he's not out-and-about, looking for Inuyasha. Myōga also sometimes serves as his messenger, telling Inuyasha of tasks he needs to accomplish to master new powers Tessaiga has gained.
 * Myōga

Tōtōsai would often meet with Inuyasha when he experienced a problem with Tessaiga. However, he greatly 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 nonetheless assists when he deems it necessary. As Inuyasha is not that bright, Tōtōsai often has to explain a great deal about Tessaiga and what tasks Inuyasha needs to complete in order to master new abilities. Lacking any fear of Inuyasha (as Inuyasha doesn't like to take lives), Tōtōsai often make wise-cracks that result with him receiving a whack to the head in response.
 * Inuyasha

Unlike Inuyasha, Sesshōmaru causes Tōtōsai great fear, forcing him to go on he run when he is asked to make a sword that rivaled Tessaiga. However, he knows that the Bakusaiga exists in Sesshōmaru and does his best to help him overcome the blade's test to see if Sesshōmaru is worthy of it. Beforehand, he reforged Tenseiga, unlocking the Meidō Zangetsua for the blade of the underworld because there was a change in Sesshomaru's heart because of Kagura. He makes a sheath for Bakusaiga once it is born, making it match its handle.
 * Sesshōmaru

Known creations

 * Tessaiga
 * Tenseiga
 * Tessaiga's sheath
 * A sheath for the Bakusaiga
 * An kusarigama-like weapon for Kohaku