TV-Series
Description
Ayumu Yamazaki is a character from the anime Peacemaker, serving as the cook and housekeeper at the compound of the Shinsengumi, the special police force around which the story revolves. She is the older sister of Susumu Yamazaki, a spy and intelligence agent working for the same organization.

Ayumu, often affectionately called Ayu-nee or big sister Ayu by those who know her, is a young woman with a pretty appearance and a naturally motherly, caring disposition. She acts as a den mother to the members of the Shinsengumi, providing warmth and domesticity within the often harsh and violent environment of the group. Her nature is particularly evident in her interactions with the young protagonist, Tetsunosuke Ichimura, for whom she serves as a kind and supportive big sister figure.

Beneath her gentle exterior as a homemaker, Ayumu is a highly capable shinobi, or ninja, working covertly for the Shinsengumi alongside her brother. She and Susumu are part of the Oniwaban, a group of spies and informants. Her role as a cook is a perfect cover, allowing her to move about the compound and the city without suspicion while gathering intelligence. Her motivation is deeply tied to her sense of duty and, more importantly, her protective love for her younger brother. She raised and trained Susumu from a young age, teaching him to suppress his emotions to become an effective operative. In a critical turn of events, after Susumu fails a mission and is prepared to commit seppuku, or ritual suicide, for his disgrace, Ayumu intervenes. She lectures him that the samurai code does not apply to a ninja in the same way and that his duty is to live and complete his mission for Vice Commander Hijikata.

Recognizing that the mission has become extremely dangerous, Ayumu takes her brother's place undercover, assuming the identity of a woman named Sen to infiltrate a location called Masuya, where enemies of the Shogunate are known to gather. She is fully aware this is likely a suicide mission, but her primary motivation is to protect Susumu, believing that if she must die, he can live on as both of them. Before leaving, she shares a poignant moment with Tetsunosuke, expressing regret that she was never a proper sister to Susumu and asking the boy to become his friend in her place. Her actions are driven by a desire to atone for the cold, unfeeling upbringing she imposed on him for the sake of their ninja training.

Ayumu's role in the story, though not lengthy, is pivotal. She is captured by the enemy, subjected to brutal torture, and killed. Her mutilated body is later found by Susumu, an event that shatters his emotionless facade and becomes a major turning point for his character, allowing him to finally grieve and connect with others. Her death profoundly affects the other members of the Shinsengumi as well, who mourn her not just as a spy, but as a beloved member of their family.

While she does not possess flashy combat abilities seen in other characters, her notable skills lie in stealth, infiltration, and disguise. Her greatest strength is her quiet competence and the emotional resilience that allows her to perform dangerous espionage while maintaining the warm and nurturing persona of the group's cook. Her legacy is not defined by a single battle, but by the emotional impact of her sacrifice, which serves as a catalyst for change in her brother and underscores the human cost of the conflict at the heart of the series.
Cast