Pinako Rockbell is an elderly woman who lives and works in the rural town of Resembool in the eastern region of Amestris. She is a surgeon, a weapon smith, and a highly respected automail engineer, and she is regarded as the founder of Rockbell Automail, the family-run workshop that serves as the town's center for mechanical prosthetics. In appearance she is very short, with long gray hair usually tied into a large bun, glasses, and a pipe she often smokes, and she is typically seen wearing an evergreen dress and a white apron. In her younger years she was tall and striking, with long brown hair, and she enjoyed a lively social life in Resembool.

Pinako's background is closely tied to the town and its families. She was the oldest and closest friend of Van Hohenheim long before he married Trisha Elric, and she was the one who introduced the two of them. She also helped deliver their sons, Edward and Alphonse Elric. Her own family suffered great losses: her son Yuriy and his wife Sarah died during the Ishval Civil War while providing emergency medical care near the battlefield, leaving Pinako to raise her granddaughter Winry Rockbell as her only surviving family. When Trisha later died of illness, Pinako took on the role of guardian for Edward and Alphonse as well, looking after all three children even though the brothers continued to live in their own family home.

In personality, Pinako is blunt, sharp-tongued, and practical, with a dry sense of humor. She and Edward constantly trade insults, particularly about each other's short stature, but the bickering masks deep affection. She is shrewd and observant, and she never treated Hohenheim with fear or suspicion, even after learning that he had not aged in decades. When Edward and Alphonse's attempt to resurrect their mother went horribly wrong, Pinako did not scold them. Instead, she performed emergency surgery on Edward to stop his bleeding and save his life, and she later fitted him with automail replacements for his right arm and left leg. She was honest about the agony of the procedure and warned Edward that a full recovery would normally take years, but she respected his determination when he insisted he could do it in one year. She also encouraged Edward to ask Alphonse directly whether he blamed him for what happened, rather than carrying guilt in silence, and she defended the brothers against authority figures, including Roy Mustang when he came to recruit Edward into the State Alchemist program.

In the story, Pinako serves as the anchor of the Rockbell home, which the Elric brothers repeatedly return to for repairs, rest, and emotional grounding. She worked alongside Winry as Edward's personal automail engineers, with Pinako building his limbs and overseeing maintenance of his leg while Winry handled the arm. She humorously notes that Edward has become her best paying customer, charging him more for urgent work. She also taught Winry the craft of automail engineering, passing on the family trade. Her reputation as an engineer extends well beyond Resembool; the automail craftsman Dominic LeCoulte remembers her by the nickname the Leopardess of Resembool, suggesting a formidable and colorful past.

Her motivations center on family and duty. She is driven to protect and support the children in her care, to preserve her family's craft, and to give Winry and the Elric brothers a stable home to come back to. She does not seek adventure or recognition, preferring the quiet life of her workshop, but her loyalty runs deep. Near the end of the brothers' journey, when Hohenheim finally returns to Resembool to die, it is Pinako who finds his body and recognizes that he died peacefully, with tears in his eyes. Throughout the series she remains a steady, unsentimental, and deeply caring presence, embodying the resilience of Resembool itself and the importance of the bonds she helped build.