Recovery Girl, whose real name is Chiyo Shuzenji, is the resident nurse and chief medical officer at U.A. High School in My Hero Academia. She is a petite, elderly woman with a hunched posture, often seen using a walking cane. Her most distinctive physical features are her large, syringe-like hypodermic needle attached to her lips, which she uses as a tool for her Quirk, and her medical uniform, which is typically adorned with a pink cape and a hat shaped like a bandage roll. Despite her frail and diminutive appearance, she is a formidable and respected figure within the hero community, having served as a medical professional for decades, even predating the tenure of the school's current principal, Nezu.

Her personality is a blend of stern practicality and deep-seated compassion. She is famously no-nonsense and frequently chides the students, particularly the more reckless ones like Izuku Midoriya, for pushing their bodies beyond their limits. She lectures them with a sharp tongue, emphasizing that healing is not a substitute for caution and that repeated severe injuries will have long-term consequences. This gruff exterior, however, masks a profound dedication to the well-being of her charges. She genuinely cares for every student and views her role not just as a healer of wounds, but as a guardian of their future health and hero careers. She can be surprisingly gentle and reassuring when the situation demands it, offering quiet comfort to those in distress.

Her primary motivation is to ensure that the next generation of heroes survives and thrives. She is driven by a pragmatic understanding of the physical toll heroism takes, and she works tirelessly to mitigate that damage. Unlike many heroes who focus on combat or rescue, Recovery Girl's motivation is rooted in preservation and sustainability. She believes that a hero's body is their primary tool, and she is often frustrated when young, enthusiastic students treat their own bodies as disposable in the heat of battle. Her life's work is a constant battle against the consequences of youthful recklessness and the brutal realities of villain attacks.

In the story, Recovery Girl serves as a crucial support system. She is the primary healer for the students, treating injuries sustained during training exercises, sports festivals, and real-world combat. Her office is a sanctuary where students recover from broken bones, severe burns, and exhaustion. She is often the one who delivers the hard truths about injury recovery, such as when she warns Midoriya that his constant use of One For All at full power is shortening his life and that her Quirk accelerates natural healing but draws on the patient's own stamina, meaning it cannot heal everything and can be dangerous for the elderly or severely weakened. She plays a pivotal role during major arcs, providing critical medical aid after attacks like the USJ incident, the training camp assault, and the war arc, where her abilities are stretched to their limits by the sheer volume of casualties.

Her key relationships are primarily with the U.A. faculty and the students. She shares a long-standing professional rapport with All Might, often scolding him for his reckless self-sacrifice and for passing on his Quirk to Midoriya, which she sees as a heavy burden. She has a deep, unspoken respect for his dedication but does not hesitate to voice her medical concerns. Her relationship with Midoriya is particularly significant; she is a constant presence in his recovery journey, acting as both a healer and a stern mentor who forces him to confront the physical price of his ambition. She also interacts frequently with other staff members, such as Principal Nezu and Eraserhead, offering her medical expertise and strategic advice during crises.

While Recovery Girl does not undergo a dramatic character arc, her role and perspective evolve subtly. As the series progresses and the conflicts become more dangerous and large-scale, she is forced to accept that she cannot heal everyone and that some wounds, particularly psychological ones, are beyond her power. She becomes more visibly weary and frustrated, not with her patients, but with the escalating cycle of violence that continually fills her infirmary. This development highlights the immense strain placed on support staff in a world overrun by villainy, showing that even the most experienced healer can feel helpless against overwhelming tragedy.

Her notable ability is her Quirk, Heal, which allows her to massively accelerate the natural healing process of a living being. She activates this ability by kissing the injured area, which stimulates cellular regeneration and closes wounds rapidly. However, this power has significant limitations. The accelerated healing consumes a great deal of the patient's own stamina and energy, meaning that while bones can be mended and lacerations closed in seconds, the patient is left exhausted and may require significant rest afterward. Furthermore, her Quirk is less effective on older individuals or those with pre-existing conditions, and it cannot regenerate lost limbs or cure illnesses. To complement her Quirk, she also possesses extensive medical knowledge and conventional surgical skills, making her one of the most capable doctors in the hero world. Her syringe-like lip tool is not just for show; it is a practical implement for administering medicines, sedatives, and other treatments when her Quirk alone is insufficient or inappropriate.