Inuyasha the Movie 3: Swords of an Honorable Ruler

Two centuries ago, the great dog-demon Tōga refused his elder son Sesshomaru’s request to own the legendary blades Tessaiga and So'unga. The decision cements the rift between brothers and sets the fate of the swords. He then travels to a samurai-guarded mansion where Izayoi is giving birth.

A brutal assault led by Takemaru of Setsuna storms the mansion where Izayoi is giving birth. Izayoi is stabbed and the manor is set ablaze, threatening the newborn's life. Tōga fights the attackers, wounds Takemaru, and enters the burning halls.

In the burning halls, Tōga wields his third blade, Tenseiga, to revive Izayoi from death's brink. He saves her and allows her to flee with the newborn. Izayoi names the child Inuyasha.

As Takemaru presses the attack, the mansion collapses around father and assailant. Tōga's spirit appears to urge Izayoi to live a long life with Inuyasha. Izayoi escapes with the infant as the structure falls.

In the present day, Inuyasha travels through the Bone-Eater's Well in a bid to reunite with Kagome. The crossing bridges the Feudal era and modern Japan. He emerges in Kagome's world and begins their shared journey.

Kagome's family uncovers the ancient sword So'unga, realizing its true identity is dangerous. Saya, the sheath-conscience, emerges to warn of the blade's threat. The discovery sets events in motion that pull Inuyasha back to the Feudal era.

Saya warns of the blade's danger, and when Inuyasha finally grips So'unga, the weapon takes control and drags him back to the Feudal era. The sudden transition thrusts him into the ancient world and against his own demonic side. Kagome and friends realize the threat is real and must intervene.

In Feudal era, Miroku, Sango, Shippo, and Kirara attempt to restrain the possessed Inuyasha. He breaks free and unleashes the Dragon Twister, overpowering them. Kagome carries Saya into the Feudal era to join the others.

Kagome joins Inuyasha, Sesshomaru, and the others in the Feudal era. Myōga provides historical context about Saya and the danger, while Totosai arrives to explain the blade's peril and its ominous power.

Sesshomaru confronts Inuyasha about So'unga's possession and orders him to stand down. Kagome uses the Beads of Subjugation to break the blade's hold, freeing Inuyasha and scattering So'unga. Sesshomaru departs with Jaken and Rin as Inuyasha vows to defeat the blade.

Tōga's spirit returns and reveals So'unga is inhabited by an ancient evil demon. Takemaru retrieves Sesshomaru's severed arm from the past and is reborn with So'unga into a new body, vowing vengeance on Tōga by killing his sons. The threat intensifies as the two swords converge with a dark purpose.

Takemaru seizes a nearby castle, crushes its army, and reanimates the fallen soldiers into an undead legion. He opens a portal to the netherworld, enabling his forces to spill into the world and threaten both eras.

Kagome and her comrades join Inuyasha and Sesshomaru for a major assault against Takemaru's undead forces. Miroku uses Wind Tunnel to wipe out the remaining soldiers, while the group strategizes to counter So'unga's power.

The only way to stop Takemaru and So'unga is to fuse Tessaiga's Backlash Wave with Sesshomaru's Dragon Strike. Though initially reluctant, Inuyasha and Sesshomaru join forces to unleash the combined attack. They destroy So'unga's body and send the blade into the netherworld as Tōga's spirit looks on proudly.

With So'unga defeated, Tōga's spirit appears to express pride in his sons as the portal closes. Sesshomaru departs with Jaken and Rin, leaving Inuyasha and his friends to survey a world returning to normal. The brothers' uneasy alliance marks a new balance between the feudal and modern realms.