Nio is a member of the Revengers, an organization that carries out revenge on behalf of the powerless. They appear as a small, androgynous child with short purple hair and yellow eyes. Despite their youthful and angelic appearance, Nio possesses a cruel and calculating mind, approaching killing as if it were a playful game and showing no signs of morality or remorse. Nio’s signature weapon is a kite whose strings are coated in tiny glass shards, which they use to deadly effect. They are first seen rescuing the samurai Raizo Kurima after he is ambushed, bringing him to the Revengers’ base. Within the group, Nio serves as an assassin, often using their innocent demeanor to get close to targets or distract them during missions. Their relationship with the other members is professional but distant, as Nio’s detachment and lack of empathy set them apart. Over the course of the series, Nio remains largely unchanged, maintaining their playful yet ruthless nature as they carry out assignments alongside their comrades.