black widow : Before I jump into her death, let’s have a glimpse of her early life, how an ordinary girl become a super heroine in the world which full of human resources.
Before bringing the black widow into a cinematic world, she was introduced in the comic novel. The Black Widow’s first appearances were as a recurring, non-costumed, Russian-spy antagonist in the feature “Iron Man,” beginning in Tales of Suspense #52 (April 1964).
There were so many novels which had been issued, based on black widow, for instance, Avengers 29 (July 1966), The Amazing Spider-Man 86 (July 1970), also been part of Inhumans, Daredevil 81–124 (Nov. 1971–Aug. 1975), The Champions (Oct. 1975–Jan. 1978), From the 1980s to 1990s, the Black Widow appeared regularly as both an Avengers member and a freelance agent of S.H.I.E.L.D.
Natasha The first and amazing-known as Black Widow is a Russian agent trained as a spy, martial artist, and sniper, and outfitted with high-tech weaponry, including a pair of wrist-mounted energy weapons dubbed her Bite.
Natasha Romanoff was known as a widow because she was arranged to marry the well-known Soviet test pilot Alexei Shostakov. However, when the Soviet government decided to make Alexei into their new operative, the Red Guardian, he had told that he has to abandon his wife. Natasha had said that he had died.
The reason for her long and youthful life is that she has gone through some experiments like biotechnologically and psycho-technologically enhanced.
Avenger Her life as an Avenger did not start smoothly she was on the mission by the Soviet Union to kill Professor Anton Vanko where she confronted the Iron man she could not succeed in the mission but during the mission she met Hawkeye and fell in love with him which make her venerable for her country, she was ordered to be killed but made her way to the Avengers.
How black widow going to help other Avengers in Avenger Endgame
There are so many theories which are circulating about avenger endgames, but the most recent one is about the black widow/Natasha.
According to writers of the film, they spoke about their original plans for Avengers 4 and stressed that they are “never writing without knowing where the end goes.“
McFeely(the writer) also said that despite Steve and Natasha not going along for the ride when it came to fighting Thanos on an intergalactic basis in Infinity War, they “have a much more significant role to play in that second film.
As the second trailer out now which clearly showing that Steve and Natasha are going to play a significant role in the Avenger4.
Come to the theory, to regain the trust of Toney Stark, Natasha will give a most significant sacrifice of her life to acquire the soul stone she would give her soul in exchange of soul stone and sparing both Steve and Tony from the tough decision. Her death would trigger the Hulk and allow him to reconnect with Bruce and merge as Hulk.