Naraku is the main antagonist of the anime Inuyasha, a half-demon born from the fusion of a crippled human bandit named Onigumo and a horde of weak demons. Onigumo, who was being tended to by the priestess Kikyo, harbored a deep, frustrated lust and obsession for her. In exchange for a mobile body and the chance to possess Kikyo, he allowed demons to devour his soul and body, creating a new entity that would come to be known as Naraku. The name Naraku itself translates to hell or underworld. As a half-demon, Naraku resented his mixed heritage and sought to become a full demon. His primary motivation throughout the story is to collect all the shards of the Shikon Jewel, a powerful artifact that can grant immense power to both humans and demons. He desires the jewel not only to become a full demon but also to gain near-invincibility and to purge any lingering humanity from his being.

Naraku's personality is defined by his ruthlessness, cunning, and manipulative nature. He is cold, calculating, and enjoys toying with the emotions and suffering of others. He is directly responsible for nearly every major tragedy in the series, including the death of Kikyo, the sealing of Inuyasha to the sacred tree, the curse on Miroku's wind tunnel, and the destruction of Sango's family and village. He orchestrates intricate schemes and traps, often using the weaknesses and emotional bonds of his enemies against them. Despite his overwhelming ambition, he is also characterized by a deep-seated loneliness and fragility, stemming from his origins as a despised cripple and his inability to truly trust anyone. His admiration for Kikyo remains a point of vulnerability, causing him to occasionally lose composure. He rejects his identity as a half-demon and views his human heart as a weakness, which he constantly tries to remove or suppress.

In the story, Naraku serves as the primary driving force of conflict. He operates largely from the shadows, rarely confronting his enemies directly except when he has a clear advantage. He often assumes disguises, most notably that of Kagewaki Hitomi, a local lord's son, to manipulate political and personal situations. As he gathers more shards of the Shikon Jewel, his power grows and he becomes more formidable, eventually transforming into a giant spider-like demon. His ultimate goal is to obtain the completed jewel and achieve absolute power, but his machinations inadvertently draw the main characters together and force them to grow stronger. He is the archenemy of Inuyasha, and their rivalry is the central conflict of the series.

Key relationships define much of Naraku's role. His relationship with Kikyo is the most fundamental; his obsession with her fuels his desire for power and his cruelty. He manipulated events to turn Inuyasha and Kikyo against each other, leading to her death. With Inuyasha, he serves as a foil, constantly testing the half-demon's strength and resolve. His relationship with his creations, such as the incarnations Kagura, Kanna, and Byakuya, is one of control and utility. He views them as disposable tools, though they each develop their own desires for freedom or loyalty, leading to internal conflicts. Kagura, in particular, yearns for independence and ultimately betrays him, leading to her death at his hands. Naraku also interacts with other characters like Miroku and Sango, having directly caused their personal tragedies.

Naraku undergoes significant development throughout the series, though it is not a path toward redemption. His power continuously evolves as he absorbs more demons and shards of the Shikon Jewel. He constantly revises and enhances his body, shedding weaknesses and refining his abilities. A major turning point occurs when he successfully gathers all the shards, completing the Shikon Jewel and fully transforming into a powerful spider demon. He also attempts to rid himself of the last traces of Onigumo's heart, which he perceives as a fatal vulnerability. He separates his heart into an infant-like avatar named Akago, believing this will allow him to act without emotional obstruction. This act ultimately creates a weakness that his enemies exploit, as Akago becomes a separate target. In the final battle, after becoming a massive spider demon, he is defeated by Inuyasha and his companions, but even in death, he attempts to drag his enemies into the underworld with him, though this final scheme is ultimately thwarted.

Naraku possesses a vast and versatile array of abilities. His body, composed of fused demons, allows him to freely decompose, regenerate, and recompose himself, rendering most physical attacks ineffective. He can extend parts of his body into tentacles or weapons that can thrust, swing, and entangle. He can generate a powerful barrier that protects him and can reflect demonic energy back at attackers. He can produce a deadly miasma, a poisonous gas strong enough to dissolve the ground, which is fatal to humans and demons alike. He commands a swarm of hellish insects called Saimyosho, whose venom is used to seal Miroku's wind tunnel. His most distinctive ability is the creation of incarnations, autonomous beings separated from his own body, each with unique powers and personalities, such as Kanna, Kagura, Goshinki, and Byakuya. He also uses a puppet technique, creating lifelike substitutes that share his will and combat prowess when he is in a dormant or vulnerable state. With the completed Shikon Jewel, his power becomes immense, allowing him to envelop entire castles in his barrier and assume a monstrous spider-like form. Despite all his power, his dependence on the jewel and his internal conflict between his demonic nature and his lingering human heart remain his ultimate weaknesses.