Toukijin is the sword that the evil sword smith Kaijinbou made for Sesshoumaru after being rejected by Toutousai to make the sword earlier (see episode 34). The sword appears in episodes 43-45. The sword is made from the teeth of one of Naraku's children or spawns named Goshinki. Sesshoumaru wants these teeth used because Goshinki was able to bite into and break the Tessaiga. Sesshoumaru uses to Tenseiga to revive Goshinki's head because dead teeth cannot be used to make the sword (Inuyasha killed the Goshinki in an earlier episode). The hate of the spirit in the teeth used to make the sword, caused the sword to seek out revenge on it's killer and took control over whom ever wielded it. The sword is extremely powerful and is later reclaimed by Sesshoumaru, who is surprisingly unaffected by the swords control and becomes it's wielder. He attempt's to use it to once again try to break Tessaiga but was unsuccessful. Sesshoumaru continues to wield the sword throughout the remainder of the series along with Tenseiga.
Submitted by Khaoticfolks