Takemaru

Setsuna no Takemaru (剎那の猛丸) was a character who appeared in the third Inuyasha movie Inuyasha the Movie 3-Swords of an Honorable Ruler where he is one of the main antagonists.

Overview
Takemaru no Setsuna was a jealous human Samurai lord who fell in love with Inuyasha's mother, Izayoi. His jealousy became so great at he attempted at her life and impaled her while she was in labor with Inuyasha. When Inutaisho, Inuyasha's father came to save her. Takemaru appeared before the yokai warrior and attempted to take him on but his challenge was easily brushed aside, costing him his left arm. Not wanting to let the Inu yokai take Izayoi away, he orders his soldiers to immediately burn down the castle. Takemaru's attempt to keep her for himself was in vain as the Daiyōkai utilized Tenseiga to revive Izayoi, allowing her to escape while he fought the desperate Takemaru to the death. Takemaru is killed offscreen when the Inutaisho draws forth Sou'unga and claims his life with the Dragon Twister.

Later on, the sword Sounga, free from Saya wanders around the land searching for a suitable host after it is driven away by Kagome calling Inuyasha to sit, attempting to save Inuyasha from Sesshomaru's poisoned claws. Reacting to the lingering thoughts of Takemaru, whose skeleton resided in the charred badlands. the evil sword revived him and fed on his desire for revenge against the Inutaisho and his kin. To further sweeten their vengeance, Sounga gives Takemaru Sesshomaru's left arm which lopped off during the Yokai's scuffle with his younger brother to wrestle control over Tessaiga. With blade in hand, Takemaru transforms into a Yokai of death and destruction and takes command of a nearby castle, killing its inhabitants and soldiers which then whose corpses he uses to raise an army of evil undead as he erects a dark castle to begin his conquest. As Inuyasha's and Sesshomaru's groups storm the castle, Takemaru comes face to face with Sesshomaru himself with Tokijin at the ready.

Though Sesshomaru is able to easily overpower him in terms of strength and even cuts him down, the Sounga simply regenerates him, mocking him that he can't be killed by another weapon already steeped in evil. It is from this realization that Sesshomaru instead draws forth Tenseiga and finally slays him, freeing him from Sounga's control. His last thoughts are of Izayoi and regretting his mistakes as his body is reduced to bone once more before his skeleton is crushed by the temple's transformation.

Later Takemaru tried to eliminate Inuyasha and Sesshomaru. But with the combined power of the Inuyasha's Backlash wave and Sesshomaru's Dragon Strike, he was vanquished.

Similarities of Past and Present of Story
Many say that InuTaisho is a two timer like Inuyasha because he mated with Sesshomaru's mother and fell in love with Izayoi and Inuyasha fell in love with Kikyo (who dies) and then Kagome (who later becomes his wife). Like InuTaisho cutting off Takemaru of Setsuna's left arm, Inuyahsa cuts off Sesshomaru's left arm. So maybe that is what Inuyasha also inherits from Inu no Taisho.