Kohaku is the younger brother of Sango, introduced in the twenty‑fourth episode as a member of a village of demon slayers. On his first mission against a spider demon at the Hitomi clan castle, the half‑demon Naraku took control of his mind and forced him to murder his own father and two other slayers. Kohaku was killed in the aftermath, but Naraku revived him by implanting a shard of the Shikon Jewel in the back of his neck. The shard erased his memories and bound him to Naraku’s will, turning him into an obedient puppet.

Within the first twenty‑six episodes, Kohaku shows no independent desires or ambitions; his every action is directed by Naraku. He carries out orders without hesitation, fighting with a demon‑bone kusarigama that he wields with growing skill. The Shikon shard amplifies his speed and strength, making him a dangerous opponent despite his youth. In battle he is methodical and alert, always planning an escape route should a confrontation turn against him.

His primary role in this part of the story is as a tragic antagonist and an emotional weapon against Sango. Naraku uses Kohaku to torment his sister, forcing her to face her own brother as an enemy. Sango’s determination to free Kohaku becomes a central motivation for her, and the group’s reluctance to harm him adds tension to their encounters. Kohaku himself shows little emotion, but the flickers of confusion or recognition that occasionally surface hint at the innocent boy he once was. These moments deepen the tragedy of his situation.

Kohaku’s development remains limited in these early episodes; he stays under Naraku’s thrall, serving as a pawn in the villain’s schemes. His relationship with Sango is defined by the gulf between her desire to save him and his enforced hostility. With Naraku, he is utterly subservient, never questioning the commands given to him. Within the main group, he is a reluctant enemy: Inuyasha, Kagome, and Miroku see him not as a true villain but as a victim of Naraku’s cruelty.

Despite his controlled state, Kohaku’s abilities as a demon slayer are evident. He fights with a kusarigama fashioned from demon bone, and the power of the Shikon shard allows him to hold his own against seasoned opponents. His tactics are cautious and efficient, reflecting the training he received before his fall. The tragedy of Kohaku in these episodes lies in his complete lack of agency: a skilled young slayer reduced to a hollow instrument of his family’s tormentor.