Margaret Elizabeth "Peggy" Carter was one of the most prominent agents of the Strategic Scientific Reserve during and after World War II and one of the founders of S.H.I.E.L.D.. Originally a code-breaker working at Bletchley Park, she joined the Special Operations Executive following her brother's death. Carter later joined the SSR, formed to fight HYDRA. On the mission in Germany she saved Abraham Erskine from Johann Schmidt. The success of her mission enabled the SSR to start Project Rebirth and develop their Super Soldier Serum to make the army of Super Soldiers. During the project she had befriended Steve Rogers, one of the project's candidates. In 1943, after the abrupt end of Project Rebirth and Rogers' transformation into the only Super Soldier, Carter assisted him in becoming the world's first superhero, eventually falling in love with him. After Rogers' disappearance in 1945, she continued the SSR's fight against HYDRA, capturing the last high-ranking HYDRA officer Werner Reinhardt, and continuing her service in the SSR once the War ended.