In the anime InuYasha: The Final Act, Inuyasha remains the central protagonist, a half-demon whose journey reaches its emotional and narrative peak. Born from the union of the great dog demon Tōga and the human princess Izayoi, Inuyasha has always existed between two worlds. With his long silver hair, white dog ears, golden eyes, and signature red fire-rat robe, his appearance reflects his dual heritage. For much of his life, this mixed lineage was a source of persecution, leading him to seek the power of the Shikon Jewel to transform into a full demon.

In The Final Act, Inuyasha’s personality retains its core elements of impulsiveness, fierce pride, and a short temper, yet these traits are now tempered by a deeper sense of responsibility. He is straightforward and often tactless, leading to bickering within the group, but this behavior masks a profoundly loyal and protective nature. His initial obsession with power has evolved; while he still seeks strength, it is now to protect his companions and defeat the machinations of Naraku, rather than to abandon his humanity. His greatest internal conflict in this final chapter involves mastering his own demonic blood, which threatens to consume him during moments of extreme stress, contrasting sharply with his previous desire to become a full demon.

Key relationships drive much of the narrative in The Final Act. His bond with Kagome Higurashi, the modern-day girl who freed him from a fifty-year seal, deepens from reluctant partnership to an unshakeable emotional reliance. While he struggles to express his feelings verbally, his actions demonstrate a clear priority on her safety and happiness, culminating in a resolution where their connection transcends time itself. Simultaneously, he must come to terms with the fate of Kikyō, the priestess he once loved. Her lingering presence and eventual death force Inuyasha to confront his past guilt and grief, allowing him to fully commit to the future with Kagome.

His rivalry with his older brother, Sesshōmaru, undergoes a significant transformation. Once solely adversaries over their father’s legacy, their dynamic shifts toward a tense mutual respect. A pivotal moment in The Final Act involves a confrontation in the underworld where Inuyasha proves himself the rightful heir to Tessaiga, his father's fang. This event forces Sesshōmaru to forge his own path, ultimately leading to the development of his unique weapon, Bakusaiga, and redefining their relationship as one of understanding rather than pure antagonism. Throughout the series, Inuyasha is supported by his loyal friends: Miroku, Sango, Shippō, and Kirara, for whom he willingly risks his life.

Inuyasha’s development in The Final Act centers on acceptance and mastery. He stops rejecting his human heritage and accepts the full spectrum of his identity. His growth is reflected in his control over Tessaiga, as he learns to wield the Meidō Zangetsuha, a technique that opens a path to the underworld. Instead of merely repurposing his father's ability, he refines it into a powerful attack that becomes instrumental in defeating Naraku. His notable abilities include superhuman strength, speed, and durability, the devastating Kongōsōha (Adamant Barrage), and the purifying backlash wave known as the Kaze no Kizu (Wind Scar). By the conclusion of The Final Act, Inuyasha has fully embraced his role as a protector, choosing a life in the feudal era with Kagome and achieving a balance between his demonic power and his human heart.