Natasha Romanoff is one of S.H.I.E.L.D 's best and most trustworthy agents. She is a master of disguise and has the ability to take down ten or more men in a couple of minutes. She goes by the alias of 'Black Widow'. She is extremely agile, fast, strong and deadly. She was a S.H.I.E.LD partner with Hawkeye aka Clint Barton.
Natasha Romanoff was born in Russia and went on to become a world-class spy. She reportedly began training towards the life of an assassin when she was just a child, and her ruthless effectiveness in later years earned her the alias, "Black Widow". At some point her life underwent a dramatic change when she was targeted for assassination herself, and the agent sent to kill her was a similarly talented combatant, Clint Barton. Instead of killing her, Barton spared her life because he had a certain respect for her and the pair developed a lasting partnership and friendship that soon lived on. Following the Barton incident, the Black Widow was drawn into a new life as an agent of S.H.I.E.L.D.
Iron Man 2
Later, during Iron Man 2, Natasha became the new assistant for Tony Stark, who, on the day she arrived, told her to go into the boxing ring while he'd ‘Google’ her finding out that she could speak French, Russian and Latin. While she was still in the ring, Hogan teased about punching her but she tackled him to the ground. She then assisted Tony while he was in Monaco. She attended Tony's birthday party and flirted with him and he started to get suspicious about where she had come from.
She appeared alongside Nick Fury when he talked to him in Randy's Donuts; Tony was surprised when he saw her in a S.H.I.E.L.D. uniform. Fury revealed her true name and she gave Tony a serum. Natasha along with Fury and Phil Coulson went to Tony's house and she was told by Fury that she will stay acting as an assistant. Even after Tony learned that Romanoff was a S.H.I.E.L.D. agent, she stayed on as his assistant more to keep an eye on him than anything. Later at Stark Industries while Tony was visiting Pepper Potts, Natasha came in and requested for Potts to sign something. When Potts left, Tony started to grill Natasha and tells her that he finds it amazing that she does what she does. Tony claims she could not speak other languages, Natasha replies in Latin, saying the phrase "Fallaces sunt rerum species", part of a famous quote from Seneca, meaning "the appearance of things is deceptive." Tony, unknowing of what the phrase means, asks her to translate, but she instead replies saying that he can either leave or that she can have him collected.Natasha attended the Expo show, when Ivan Vanko took control of Hammer's Drones. Natasha ran out and found Hogan and told him to drive the car to get her to Hammer Industries. After changing into a S.H.I.E.L.D. uniform during the drive, she broke into Hammer Industries to stop the drones. She encountered and took out several security men. Using technology at Hammer Industries, she managed to get control over War Machine's suit.
Natasha Romanoff is played by Scarlett Johansson and appeared in Iron Man 2, The Avengers, Captain America: The Winter Soldier, Avengers Age of Ultron, Captain America: Civil War, Avengers: Infinity War, Avengers: Endgame and her own upcoming Black Widow movie.