Agent 13
Agent 13, born Sharon Carter, is an American woman and agent of S.H.I.E.L.D. She bears a striking resemblance to her older sister, who had a romantic relationship with Captain America during World War II.
In 1965, Agent 13 was involved in a mission to transport Inferno 42, a highly volatile element capable of leveling a major city if weaponized. As she transported the canister containing Inferno 42, she ran into Steve Rogers, also known as Captain America. Rogers seemed to think they had met, while Sharon brushed off the idea that he could have been her sister's old boyfriend. As the two parted, Agent 13 was attacked and targeted by Batroc the Leaper, a mercenary hired by an unknown opposition group. Rogers returned in his Captain America suit, and he and Batroc fought. The canister was damaged and Inferno 42 began to leak into the air. She ran off with it as the men fought, but they soon chased after her upon realizing that the Inferno 42 could detonate if left unchecked, causing mass devastation.[1] Before long, the energy leaking out of the package had a deleterious effect on Agent 13, who passed out. Cap and Batroc resumed fighting, and Batroc was able to get the upper hand and retrieve the package—however, Agent 13 managed to switch the canister with a decoy, and recovered well enough to bring the real thing safely into S.H.I.E.L.D. custody. She was checked in to the hospital for Inferno 42 poisoning.[2]