Who she is: Sharon Carter, a.k.a. Agent 13
Her power: No superpowers, but she’s an all-around badass like her great-aunt, Peggy Carter.
Her story: When Sharon Carter first appears in Captain America: The Winter Soldier, she went by Kate, and seemed to just be Steve Rogers’ next-door neighbor, with whom the superhero enjoyed a casual flirtation. However, when Nick Fury was shot inside Rogers’ apartment, she burst in with a gun and revealed she was “Agent 13,” a S.H.I.E.L.D. operative meant to keep a watchful eye on Captain America. After Captain America was disavowed, she was dubious of the accusations against him, and when Hydra took over S.H.I.E.L.D. headquarters in the film’s climax, she helped lead a resistance against the shadow group.
She next appeared in Captain America: Civil War, having taken a job with the C.I.A., and turns up at Peggy Carter’s funeral, where it’s revealed for the first time that Peggy was Sharon’s great-aunt. She passes classified information to Rogers, which helps him and Sam Wilson find Bucky Barnes, and when all three are brought in later, she helps Steve eavesdrop on Barnes’ interrogation. She reappears briefly soon thereafter, when she helps Rogers, Wilson, and Barnes evade capture and shares a quick kiss with Captain America, which isn’t as weird as it might normally be to have a film’s hero make out with the great-niece of a woman he had romantic feelings toward.
Played by: Emily VanCamp
Currently, Sharon Carter is: Presumably still with the C.I.A.
Where will we see her next? Unknown, although Avengers: Infinity War—due in 2018—might be a good bet.