Namie Yagiri is a twenty-five-year-old woman who serves as the chief of Yagiri Pharmaceuticals, a company involved in clandestine research in Ikebukuro. She is the older sister of Seiji Yagiri, toward whom she harbors incestuous romantic feelings, a fixation that defines nearly every aspect of her life. She presents herself as cold, demanding, and professional, her default expression stoic or angry, and she rarely shows warmth to anyone except her brother. She believes that the emotions of others are insincere and that only her own devotion to Seiji is genuine. Her primary motivation is to protect her brother and be loved by him, even if that means she remains only in the role of the older sister. When Seiji became obsessed with the disembodied head of Celty Sturluson, Namie viewed the head as a rival and sought to eliminate it. To keep Seiji close, she orchestrated an elaborate deception: rather than actually attaching Celty’s head to the body of Harima Mika, she arranged for Mika to undergo plastic surgery to resemble Celty, then convinced Seiji that the head had been successfully grafted. This lie allowed her to maintain some control over the situation, but Seiji eventually fled with the head, leaving Namie heartbroken and determined to find him. She turned to the information broker Izaya Orihara for help, and after Yagiri Pharmaceuticals was bought out by an American competitor, she made a deal with Izaya and became his secretary, living with him while continuing her search. Though she works alongside Izaya, their goals differ: Izaya thrives on chaos and conflict, while Namie remains singularly focused on recovering her brother. In her role at Yagiri Pharmaceuticals, she oversaw the kidnapping of people whose disappearances would go unnoticed, using them for unlicensed experiments. She relied on the underground doctor Shinra Kishitani to keep the secret of Celty’s head and to assist with certain tasks. Her relationship with Shinra is one of guarded cooperation; she trusts him only as far as necessary. After losing her position, she adapts to a more domestic arrangement with Izaya, handling paperwork and errands while maintaining her cold demeanor. She is physically described as a curvaceous woman with brown eyes and long dark brown hair, typically wearing a white lab coat over a dark red mini skirt, black tights, and a green turtleneck. Her notable abilities include her expertise in pharmaceuticals and biological research, her aptitude for manipulation and deception, and her willingness to conduct morally questionable experiments for personal ends. Throughout the story, she shows little development beyond her obsessive love for Seiji, though she becomes more pragmatic in her alliance with Izaya, continuing to act as his right hand while never losing sight of her own objectives.