Takemaru

was a character who appeared in the third InuYasha movie Swords of an Honorable Ruler where he is one of the main antagonists.

History
Takemaru no Setsuna (Takemaru of Setsuna) was a jealous human Samurai lord who fell in love with Inuyasha's mother, Izayoi who was, at the time, in love with Tōga and pregnant with their son. His jealousy became so great that he attempted to take her life and impaled her while she was in labor with Inuyasha. When Tōga came to save her, Takemaru appeared before the daiyōkai 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 daiyōkai take Izayoi away, Takemaru ordered his soldiers to immediately burn down the mansion. Takemaru's attempt to keep her for himself was in vain, as the daiyōkai utilized Tenseiga to revive Izayoi, giving her the Robe of the Fire-Rat. Takemaru then approached Tōga with the intention of fighting him to the death, even going so far as saying that they shall "journey together into the netherworld". Tōga simply replied with the word "Inuyasha". Initially surprised by what he said, Tōga told Takemaru that it was the infant's name, to which Izayoi accepted, and escaped under Tōga's orders while he used Sō'unga's Dragon Twister as he fought the desperate Takemaru to the death. Both Takemaru and Tōga are killed when the castle collapsed on them.

200 years later, Sō'unga (freed from Saya) wandered around the land searching for a suitable host. Reacting to the lingering thoughts of Takemaru, whose skeleton resided in the charred badlands, the evil sword used a undead ogre as a temporary host to take him there, and then proceeded to Takemaru, while feeding on his desire for revenge against Tōga and his kin. Takemaru's skull eyes glowed red and his skeleton body glowied white as he came out of his grave, while the dirt with roots and dead leaves formed new skin form him. To further sweeten their mutual desire for vengeance, Sō'unga presented Takemaru Sesshōmaru's left arm, which had been lopped off during his previous scuffle with Inuyasha at their father's tomb. With the blade in hand, Takemaru transformed into a yōkai of death and destruction and took command of a nearby castle soon after, killing all its inhabitants and soldiers whose corpses he used to raise an army of evil undead, as well as erecting a dark castle to begin his conquest. As Inuyasha's and Sesshōmaru's groups storm the castle, Takemaru came face to face with Sesshōmaru himself with Tōkijin at the ready after he was about to kill Kagome and Rin due to their association with Tōga's sons.

Though Sesshōmaru was able to easily overpower him in terms of strength, he was unable to kill him due to being undead. This later led him to lose Tōkijin and was cornered by Takemaru. As Takemaru was prepared to kill him, Sesshōmaru dodged his attack and attempted to reclaim his sword, but was stopped by Tkaemaru. This was a diversion, however, so that Sesshōmaru could instead reach out for the Tenseiga due its ability to kill the living dead. Sesshōmaru soon managed to bisect him with his show, but Takemaru was restored a moment later by Sō'unga, to which Takemaru followed by mocking him due to his inability to kill him as a corpse. As their battle continued, Takemaru proclaiming that he is disappointing his father's fang. Inuyasha then arrived at the scene and does battle with Takemaru after a preemptive Wind Scar attack. Crossing blades, Takemaru looked at Inuyasha and saw a resemblance to Izayoi. He then bitterly revealed to Inuyasha that he was the one who had taken his mother's life, greatly angering the hanyō. While Sesshōmaru and Inuyasha begin to bicker over fighting him, Takemaru tried to take this opportunity to kill them both with the Dragon Twister. Inuyasha, however, rushed forth and drove him back with an unprecedented amount of power. Takemaru was baffled by this, which prompted Inuyasha to explain that it was his human side that gave him the persistence and willpower to fight to the end, as well as the desire to protect those close to him. With one final push, he finally blasted Takemaru through a wall, defeating him. Takemaru's last thoughts and visions were of Izayoi telling him to leave the grounds of their old castle, as it was for his own protection because she wanted him to live, and, finally realizing she didn't betray him and regretted his mistakes, he realized he never felt hate for Izayoi as his body disintegrates back into a Skeleton, followed by Sesshōmaru using the Tenseiga to have his soul pass on in peace. Sō'unga then decided to fight the two brothers itself, causing Takemaru's skeleton to be crushed following the destruction of his castle.

Personality
Takemaru is first depicted as a man who appeared to care for Izayoi, but his jealousy over the Tōga consumes him so that he became a danger to all around him and attempted to take Izayoi's life. It seems like Izayoi cared for him as well as she attempted to save him from Tōga's wrath. When resurrected at the behest of Sō'unga, Takemaru's jealousy gradually turned to insanity, wanting to slay each and every human, no matter their age, if they shared a relationship with demons, causing him to view them all the same way that he viewed Izayoi. It is shown though that he wasn't all bad as when he has visions of Izayoi (possibly her soul speaking to him) he realizes he never held anger against her and always loved her.

Physical Description
Takemaru first appears as a human adult male with fair skin and black hair tied up in a short fashion. When he was still alive, he wore traditional samurai lord armor featuring a distinct crimson sheen. After being revived as a specter, most of his armor has been worn down but his hair grew to its full length, much past his shoulders. After taking hold of Sō'unga, Takemaru took on a slightly demonic appearance featuring blue spots and markings on the right side of his face and a long horn growing from his forehead along with his hair becoming red and shaggy. His eyes gained a yellow sclera and pupils became red. He wore a dark jacket, white hakama and crimson armor that resembles a dragon with spikes jutting out and a large blue jewel in the middle of his chestplate.

Powers & Abilities

 * Master Swordsman: As a samurai lord during his life as a human, Takemaru possessed incredible skill in swordsmanship, he could single-handedly kill a guarded fortress of samurai warriors with great ease. When empowered by Sō'unga's demonic energy, he could not only to go toe-to-toe with Sesshōmaru, but actually disarm him at the outset of the duel, and later hold both him and Inuyasha back. Also as seen in the flashback 200 years ago, Takemaru was able hold up against Tōga himself wielding Sō'unga (albeit the demon was weakened by his wounds from Ryūkotsusei). However, Takemaru in many ways is still notably inferior to Tōga as a swordsman, as Takemaru had lost his arm to Tōga in a momentary exchange minutes earlier. It's possible that Takemaru only lasted in the later duel as Tōga was weilding Sō'unga, instead of Tessaiga. Sō'unga has a personality of its own, so despite being much more powerful that the Tessaiga, it was constantly trying to possess Tōga, meaning Tōga was fighting Takemaru and Sō'unga both at once.
 * Enhanced Endurance: Takemaru possesses enough endurance to recover from a severed arm and sword wounds in moments and proceeded to fight against the wounded and weakened Tōga for some time before they both died in the collapsed burning mansion.
 * Reanimation: Upon being resurrected by Sō'unga as his vessel for the time, Takemaru possesses some unique abilities due to becoming an undead that made him a dangerous opponent.
 * Enhanced Strength: When he was possessed by Sō'unga, Takemaru has enough physical strength to evenly combat against Sesshōmaru and Inuyasha despite the former being a daiyōkai and the latter being a powerful hanyō whom have do doubt greater strength than an ordinary human.
 * Enhanced Speed: As an undead specter possessed by Sō'unga, Takemaru became fast enough to contend with both Sesshōmaru and Inuyasha with him being able to easily parry a blow from the latter with only arm while standing still. Takemaru even managed to slay an entire group of human samurai without getting a scratch on himself.
 * Enhanced Durability: While having Sō'unga in his possession, Takemaru endured a powerful point-blank Kaze no Kizu from Inuyasha that sent him through a wall within the phantom castle and greatly damaged but remained conscious. Though the blow caused him to finally see the sacrifice Izayoi attempted to make for him and the other men at the mansion that caused him to finally pass on.
 * Regeneration: As a result of being possessed by Sō'unga, Takemaru is able to regenerate from even the most fatal of wounds and could even recover from a slash of the Tenseiga as his hate prevented him from passing on.

Weapons

 * Warlord Armor: When he was still alive, Takemaru adorned a set of red armor, including cuirass, gauntlets, grieves and helmet. After his death, this was worn down but restored and transformed after taking a hold of Sō'unga.
 * Naginata: While still a living samurai, Takemaru brandished a samurai spear to kill Izayoi just after she gave birth to Inuyasha though Tōga resurrected her with Tenseiga.
 * Katana: Before dying with Tōga in the burning mansion, Takemaru wielded an ordinary samurai sword in an attempt to defeat the demon.
 * Sesshōmaru's Left Arm: Due to being a reanimated human, Takemaru needed to connect Sesshōmaru's severed left forearm in place of his own severed left forearm in order to use the powers of Sō'unga in particular with that of the Dragon Twister. Though he is unable to fully control the demonic powers of the arm as he commented that the arm doesn't like following his instructions after he used Dragon Twister to slaughter an army of samurai and collapsed in exhaustion.
 * Sō'unga: The third sword once possessed by the Dog General. It fed on Takemaru's lingering desires as a specter and restored him to life and gave him great power, promising him supreme conquest if he was to kill Inuyasha and Sesshōmaru. While their swords, Tessaiga and Tenseiga, could destroy a hundred demons in one swing and save a hundred lives in one swoop, Sō'unga could summon forth a hundred corpses from Hell itself to serve the wielder. Unlike the other two swords, Sō'unga is possessed by an ancient and malevolent demon spirit.
 * Gokuryūha: As a result of wielding Sō'unga, Takemaru can, at will, invoke the powerful Dragon Twister which allows him to summon forth the powers of a hell dragon and utilize its power in the form of a massive twister of demonic power strong enough to level a fully fortified castle single-handed.
 * Phantom Castle: In his attempt at revenge against Sesshōmaru and Inuyasha for Tōga, Takemaru used Sō'unga to create a phantom castle similar to Naraku where he resides in the center while the undead army risen by him fight both groups outside.
 * Reanimation: After killing the samurai army that originally resides in the castle, Takemaru has Sō'unga reanimate them as undead soldiers like him though they act more like mindless zombies incapable of thought and speech. He does this by raising Sō'unga above while standing in a tower of the phantom castle and then the blade of the sword drips out blood that initiates the process of reanimation when it touches the corpses.

Trivia

 * Takemaru's full title, "Setsuna no Takemaru" (の), literally translates as "Violent/Savage/Cruel/Bold Circle/Perfection" (Takemaru) "of the Moment" (Setsuna no); and all together (Setsuna no Takemaru) can rather fittingly be transliterated as "In the Heat of the Moment."
 * Typically in feudal Japan, most people did not have surnames unless they were from a noble family in which they would use the name of the place or clan they were from. Takemaru of Setsuna could signify that Takemaru is from the Setsuna clan.
 * It is never revealed what the precise nature of his relationship with Izayoi was, but it seems that she trusted him to actually be relieved (mistakeningly) when he came to her as she was having Inuyasha, and she really did try to save him from the Tōga (who was her own husband). So it's very possible they were close, maybe friends even.
 * Takemaru's seiyū, Yasunori Matsumoto, also voiced several characters from Rumiko Takahashi's anthology series . They include Keiichi, Ruriko Tonegawa's husband, Takanezawa, amd Yoshio Hirooka.