Iron Man, also known as Anthony Edward "Tony" Stark suffers a severe chest injury during a kidnapping. When his captors attempt to force him to build a weapon of mass destruction, he instead creates a mechanized suit of armor to save his life and escape captivity. Later, Stark develops his suit, adding weapons and other technological devices he designed through his company, Stark Industries. He uses the suit and successive versions to protect the world as Iron Man. Although at first hiding his true identity, Tony Stark eventually declared that he was Iron Man in a public announcement. Iron Man is a founding member of the superhero team, The Avengers. Iron Man is arguably the most well known Marvel character in the entire Marvel universe.
Spider-Man is a fictional superhero created by writer-editor Stan Lee.In the stories, Spider-Man is the alias of a kid named Peter Parker, an orphan raised by his Aunt May and Uncle Ben in New York City after his parents Richard and Mary Parker were killed in a plane crash. He Became Spider Man after a bite from a radioactive spider; these include clinging to surfaces, shooting spider-webs from wrist-mounted devices, and detecting danger with his "spider-sense".
Hulk is the alter ego of Bruce Banner, a physicist who physically transforms into the Hulk under emotional stress. Bruce Banner becomes the Hulk after being exposed to gamma rays from a bomb that triggers the secret sauce implanted in him as a kid by his mad scientist father.
Captain America is the alter ego of Steve Rogers, a man enhanced to the peak of human perfection by an experimental serum to aid the United States government's efforts in World War II. Captain America was designed as a patriotic supersoldier who often fought the Axis powers of World War II. The character wears a costume bearing an American flag themed suit, and he utilizes a nearly indestructible shield that he throws as a projectile.
The Black Widows real name in the movies is Natasha. The Black Widow strives to make up for the bad she had done in the past by helping the world, even if that means getting her hands dirty in the process.