Natalia Romanova (Earth-1955)

"How many more jobs... How long will it take... I don't know if I can do it... Even if I could forgive myself... This is what I am now. And you'll never know who I was before."

- - Black Widow to Batman

Natalia Alianova Romanova is a former agent of the KGB who became the Black Widow, their own version of the super soldier. She eventually defected to S.H.I.E.L.D. after becoming romantically involved with Hawkeye, participating in multiple missions with him.