Natasha Romanoff / Black Widow

Black Widow (real name "Natalia Alianovna "Natasha" Romanova") is a fictional character in the Marvel Comics Universe. She is a highly trained and former russian spy, who was originally an antagonist of Iron Man and other heroes. Eventually became a superheroine, defecting to the United States and became the partner of Captain America, Daredevil, Winter Soldier and Hawkeye. In addition, Black Widow became an agent of S.H.I.E.L.D. and later the superhero group, the Avengers.

Iron Man (Volume 1)
 Issue #269 

The Hollow Man (June 1991)