Before Gwen's death, she was seduced and impregnated by Norman. She gave birth to premature though fully grown twins while living in Europe. After her death, Norman found and raised the twins, convincing them that Peter Parker was their father and that he had killed their mother as Spider-Man. Their upbringing made the twins want revenge. Having been born with born with powers similar to Osborn's Goblin Powers, both twins aged at an accelerated rate. Sarah quickly bore a striking resemblance to her mother, which caused confusion when Sarah was unmasked by Peter while trying to kill him.
Finding out more information about the twins from a combination of clues on a letter they used to draw him out and memories Mary Jane had of Gwen and Norman arguing while Harry was in the hospital, Peter attempted to try to convince the twins that Norman had been lying to them. Instead, the police intervened and opened fire on all of them. Sarah received a bullet wound while her brother fell into the river.
Peter took Sarah to the hospital, but her body refused all blood transfusions until Peter offered his. She learned that he was telling the truth just as her brother crashed through the hospital window and dragged Peter out to kill him.
In his weakened state, Spider-Man seemed to be no match for Sarah's brother, who before had seemed only a little unstable, but now had become insane due to a second inoculation of the Goblin Serum. Sarah was able to save Spider-Man by shooting her brother's glider and causing him to crash and contract amnesia.
In the confusion, Sarah secretly took her brother back to Paris, where she cared for him at the Osborn estate until the pressure from local drug dealers to repay a debt her brother had incurred became too much for her and she attempted suicide. Peter was called to the hospital as her emergency contact and came to Paris to help. While he was with her, Mary Jane went looking for him at the estate, and inadvertently caused Gabriel to escape in a crazed state.
After cutting a deal with Interpol to catch the dealers, Sarah joined the organization to attempt to find her brother.
Powers and Abilities
Sarah Stacy displayed super strength, reflexes, healing, and endurance as well as accelerated aging all due to the inherited powers from Norman Osborn.
- Superhuman Strength: The Goblin Formula in Norman's genes was passed in some amount to Sarah, fortifying her musculature, connective tissue, and bone structure, and granting her superhuman strength to some degree. It is unlikely she possessed sufficient strength to lift more than 800 lbs, as her brother was able to with a 'second dose' of Goblin Serum.
- Superhuman Stamina: Her father's genes increased the overall efficiency of her musculature. As a result, her muscles produced less fatigue toxins during physical activity than the muscles of normal humans.
- Superhuman Durability: Her father's genes fortified all of Sarah's bodily tissues, making them far tougher and more resistant to injury than normal humans.
- Superhuman Reflexes: Sarah's reflexes were similarly enhanced by her father's genes, and are superior to those of the finest human athlete.
- Regenerative Healing Factor: Sarah's genes increased her metabolism, allowing her to heal damaged tissue much faster and more extensively than a normal human is capable of.
- Gifted Intelligence: Sarah seemingly received enhanced mental capacities and creative talents, from her father's genes, granting her a gifted intelligence. It should be noted that she was considered 'the smart one' of the twins by Norman.
- Fighting Skills: Sarah had some training in hand to hand combat before attempting to kill Peter Parker, and presumably had more after joining Interpol.
- Rapid Aging Factor: Before receiving a blood transfusion from Peter Parker, Sarah aged at a much faster rate than humans (physically aging about 2–3 years in one chronological year).
- In the aftermath of Brand New Day, it is unknown if Sarah continues to exist as she has not been specifically mentioned. Her brother Gabriel mysteriously returned to overthrow Harry Osborn as rightful heir to the Osborn legacy, but Sarah was never mentioned.
- Unlike her brother, Sarah has no dual persona yet.
- Sarah's last name was never officially revealed. It is possible that it is her mother's, her biological father's, or her alleged father's, but it is assumed to be her mother's.