Episode 182

True Heir is the 15th episode of InuYasha: The Final Act.

Summary
Sesshōmaru wants to see if Inuyasha is worthy to wield the Meidō Zangetsuha, so he challenges him to see if he can take the technique he worked so hard to master. Naraku decides to make use of Sesshōmaru's hatred by giving him a familiar unfair advantage, hoping the fight will end with Inuyasha's death.

Plot
Annoyed that Inuyasha's group is still with him, Kohaku and Rin, Jaken demands to know why they haven't left. Inuyasha rudely explains that "you shrimps can't defend yourselves." This angers Jaken, who responds "who you calling a shrimp!?" Inuyasha then wonders if Jaken wants to be taller, grabbing and stretching the imp. As Jaken demands to be let go, Kagome tells Inuyasha to stop; when he doesn't she makes him Sit! Unfortunately, Inuyasha falls on top of Jaken, squashing the imp and making him dizzy. Rin sees Sesshōmaru arrive, and goes to greet him.

A flashback shows Sesshōmaru watching waves crash by a shore. A voice asks Sesshōmaru if should be getting back soon, making him launch a Meidō at the nearby hill. Once the Meidō subsides, Byakuya of the Dreams appears on his origami crane; he's impressed Sesshōmaru tried killing him without hesitation. He goes on to explain that he has a gift for Sesshōmaru, before landing next to him. Byakuya explains he knows all about Tenseiga how was originally part of Tessaiga. Angered by the reminder, Sesshōmaru lunges his claws at Byakuya, who teleported away; Sesshōmaru now holds the fragment of Kanna's Mirror Demon.

In the present, Sesshōmaru demands Inuyasha draw his sword. When he fails to comply, Sesshōmaru launches a Meidō as a warning; barely missing Inuyasha and Jaken. Inuyasha is annoyed Sesshōmaru is still obsessed with Tessaiga, complying by drawing his sword. Sesshōmaru remembers Byakuya's explanation about the fragment, having shattered it and sprinkled the dust on Tenseiga; he knows it's one of Naraku's traps, but decides that it's one worth springing. Tenseiga glows and Inuyasha attempts the Wind Scar, only to find it isn't working. Tenseiga then transforms, taking on the appearance of Tessaiga's transformed state. Sesshōmaru unleashes a Wind Scar, shocking Inuyasha who detects a familiar scent on the blade; he demands to know why he can smell Naraku's scent on Tenseiga.

However, Byakuya's voice cuts in, explaining that Inuyasha is smelling his scent. Everyone looks up to find him flying above on his origami crane; he explains he gifted Sesshōmaru with a fragment of Kanna's Mirror Demon. Shippō becomes shocked by this, remembering how hard it was to defeat the Mirror Demon. Rin yells for Sesshōmaru to not seek help from Naraku as he's evil, going on to explain that while he was gone, Kohaku was attacked by Naraku. Byakuya becomes annoyed by the "audience", deciding to send Sesshōmaru and Inuyasha somewhere they can fight in peace; he splashes water from his gourd around them, creating a miniature moon. It floats up into the sky before seemingly collapsing into itself. Sango wonders where they've gone, only for Byakuya to says "good question"; she tosses Hiraikotsu at him, only for Byakuya to teleport away.

Inuyasha and Sesshōmaru, elsewhere, find themselves in another dimension filled with lesser demons uninterested in them, with floating chunks of land above a purple sea. Sesshōmaru is thankful for Byakuya's assistance, and resumes fighting Inuyasha; both are thrown backwards when their blades clash. Inuyasha is disappointed in Sesshōmaru for sinking low enough to use Naraku's help. Sesshōmaru explains that he wants Inuyasha to prove he's the rightful heir to Tessaiga, nothing more; if Inuyasha proves himself weak, Sesshomaru will get rid of both swords. Amused, Inuyasha asks if Sesshomaru will let go of his attachment to their father's blade. Sesshomaru only retorts "Try me."

Back on Earth, everyone is still shocked by what happened; Kohaku is just as shocked as Rin about Sesshōmaru using Naraku's power. Shippō then notices the sky is getting darker as a blast of lightning touches down in the middle of the group; it's Tōtōsai and Mō-Mō. Tōtōsai is surprised the battle between his blades has begun so soon, making everyone wonder if he can see the fight. He asks them if they want to see it, compling with their request to see it by bonking Mō-Mō's head with his hammer, making his ox's eyes act like a movie projector - it shows the fight between Inuyasha and Sesshōmaru.

Sesshōmaru uses the Adamant Barrage to attack Inuyasha, thinking to himself how disappointing their battle is turning out; he quickly finds that the barrier of Tessaiga's sheath protected him, using the Red Tessaiga on him. Inuyaha is thrown into the sea below. Byakuya's eye demon watches the battle, making him comment on how much Sesshōmaru hates Inuyasha. Naraku explains that it's Sesshōmaru's hatred of Inuyasha that makes him easily exploitable; all they did was give him a reason to attack and he took it, knowing full well that it was one of his traps. Byakuya then reports that Inuyasha was sent flying. Sesshōmaru watches the water for Inuyasha to emerge, slicing a lesser demon in half when it comes at him. Inuyasha comes out from behind it, slamming Tessaiga to the ground in an attempt to hit him. However, Sesshōmaru simply takes new footing higher above.

As everyone watches Tōtōsai's projection, they notice that Inuyasha has transformed again; his demon blood has awoken to protect him. At the same time, Sesshōmaru thinks Inuyasha transformed out of desperation. Just like his last time fighting against the Mirror Demon's power, Inuyasha retains his sanity; Tessaiga is seeking out his demonic energy. He clashes blades with Sesshōmaru, gaining back some of the powers stolen from Tessaiga, which then flows into him. Inuyasha launches a Wind Scar, Sesshōmaru counters it with the Backlash Wave; Inuyasha copies the move, with the end result of two Backlash Waves creating tornadoes of water that star ripping apart the lesser demons. Miroku is left impressed by the result of two Backlash Waves canceling each other out.

Inuyasha charges to attack Tenseiga again to take back Adamant Barrage, but Sesshōmaru launches a full-powered Meidō Zangetsuha; though Inuyasha tries resisting its pull, he's sucked inside. Sesshōmaru thinks to himself about how the Meidō Zangetsuha is a technique he trained for and mastered; if Inuyasha is destined to take it from him, now is the time to prove it. At the same time, Byakuya reports to Naraku about what has happened. Intrigued, Naraku tells him, he wants to see it; a tentacles from Naraku's head exits his barrier and enters Byakuya's eyesocket. Disgusted by Naraku's method of trying to see the battle, Byakuya asks if he can actually see. Naraku confirms that he can, and is pleased at the sight of Inuyasha hurtling down the Path to the Underworld.

Inuyasha asks Tessaiga what he's supposed to do, only for his blade to remain silent. Seeing that Inuyasha isn't doing anything to try escaping, Sesshōmaru sees that Tōtōsai was wrong and discards the heirloom from his father into the Meidō. However, when he does, Tenseiga resonates with Tessaiaga, turning into its Dragon-scaled form. Tōtōsai wonders if Inuyasha will able to understand the will of Tessaiga, only for everyone to agree that Inuyasha will. However, Shippō admits Inuyasha is stupid and thick-headed while Jaken adds Inuyasha is mean. Elsewhere, Byakuya asks Naraku if the Dragon-scaled Tessaiga was the from that cuts a foe's demon vortex; Naraku confirms this, but because the Path to the Underworld isn't a demon, it has no demonic energy Inuyasha can cut.

Inuyasha then notices his own demon vortex has appeared, realizing Tessaiga wants him to cut it; Sesshōmaru believes it will mean Inuyasha taking his own life, wondering if his brother can really do that. Believing in his blade, Inuyasha cuts his demon vortex, but unlike what Sesshōmaru believed, the energy flows into Inuyasha and Tessaiga, expanding the vortex to the point of where it's eating the Path to the Underworld. Sesshōmaru realizes this is the proof that he's been waiting to see. Byakuya comments that Naraku's trap has actually made Inuyasha stronger; he asks Naraku what he'll do now. Naraku explains that he'll simply have to take matters into his own hands, doing so with the very blade Sesshōmaru abandoned. Inuyasha is almost done with destroying the Meidō, but adamant spears become lodged in his back; he turns to see Tenseiga floating behind him.

Naraku's voice echoes, laughing that Tenseiga is still coated with the fragment of Kanna's Mirror Demon; the blade is now like a part of him, just like the Mirror Demon was. Sesshōmaru notices Naraku's interference and jumps into the Meidō while Inuyasha fights off adamant spears. However, the blade soon returns to Sesshōmaru; Naraaku reasons that since Inuyasha has weakened, Sesshōmaru has now returned to finsih him off. Naraku tells that he may do as he wishes. However, Sesshōmaru knows what needs to be done, and once more engages Inuyasha in battle; he snaps Tenseiga over Tessaiga, tossing the blade aside. Tessaiga returns to normal along with Inuyasha, becoming a black blade. Naraku laughs, calling Sesshōmaru a fool for now they've lost their only way to exit the Path to the Underworld. At the same time, everyone else asks Tōtōsai how Inuyasha and Sesshōmaru can escape the Path to the Underworld, only for him to say it's impossible now.

The Adamant spears in Inuyasha's back secrete miasma, knocking him out; Naraku taunts them, saying they're now destined to go to the netherworld. Sesshōmaru is annoyed Inuyasha passed out so easily, but knows its because half-demons are weaker than TRUE demons. He removes the spears and punches Inuyasha to wake him. He goes on to explain the Meidō has closed, and that it's up to Inuyasha to get them back to the World of the Living. Inuyasha is left questioning what to do with the new Tessaiga, wondering what he's supposed to cut. At that time, their bodies begin vanishing as they're pulled closer to the blackhole leading to the Underworld. Inuyasha sees a light shining in the blackhole, realizing he needs to cut it; he does so and a Meido opens in the World of the Living.

Inuyasha falls face-first to the ground, as Tessaiga reverts; Tōtōsai sees something fall from the Meidō. Sesshōmaru is greeted by his companions as Jaken cries, feeling grief for his master losing his only offensive weapon. However, Sesshōmaru could care less and turns to leave. Tōtōsai stops him, pointing to the object that fell from the Meidō with them; it's a restored Tenseiga. Though now the blade cannot be used to kill, it can still be used to heal, which makes it powerful as a weapon meant to kill. Sesshōmaru is left annoyed, wondering if he's now supposed to be charged with the task of healing people; he takes off without the blade. Rin takes it instead, promising to give Tenseiga to Sesshōmaru once he's in a better mood. Sango is left saddened as Kohaku leaves again.

Inuyasha asks Tōtōsai what will happen to Sesshōmaru now that everything their father left them is his. However, Tōtōsai tells Inuyasha that he'd better focus more on mastering the Black Tessaiga instead, he wouldn't have gotten free from the Path to the Underworld if it wasn't for Tenseiga's help; it was the light he saw. Regarding Sesshōmaru, Tōtosai explains that very soon, he'll have his own sword; an even better sword, one that never belonged to his father.

Trivia

 * Sesshōmaru's mental picture of Naraku depicts him as he is now. However, Sesshōmaru's last meeting with Naraku was before he absorbed Mōryōmaru and killed Kikyō, meaning he should have pictured Naraku as he looked since their fight in the Borderland.
 * It is quite strange that the Adamant Barrage didn't break through the barrier generated by Tessaiga's sheath, but the "Crimson Tenseiga" could.
 * The miniature moon created by Byakuya for transporting Inuyasha and Sesshōmaru to another dimension is anime-only; in the manga, the scene just shifts to the dimension after every is surprised by their disappearance.
 * This is the only time Naraku uses Byakuya's "eye demon" to spy on his enemies.
 * Something very curious about this is that this espisode is actually the OVA Black Tessaiga shortened from 30 minutes to 21.
 * In the original OVA released in 2008, Kagome's neckerchief is like in the first series InuYasha but in the edited version to turn it into Episode 15 FA, its stretch goes up to her sides.