Iron Widow

Iron Widow is the het ship between Tony and Natasha from the MCU fandom.

Canon
IRON MAN 2

Natasha was sent by Nick Fury to spy on Tony Stark once they realized he was ill. She was placed at Stark Industries as a legal assistant named Natalie Rushman. Tony immediately took an interest in "Natalie," which she used to her advantage to gather intel about him and assess whether he was suitable for membership in the Avengers Initiative.

After Tony's disastrous birthday party, Fury confronted Tony about his situation at Randy's Donuts. There, Natasha, wearing her S.H.I.E.L.D. uniform, introduced her true self to Tony. She gave him a shot of a serum to temporarily reduce the effects of his palladium poisoning, giving him time to work on a cure.

Later, while Tony battled Ivan Vanko's Hammer Drones and James Rhodes, whose armor was controlled by Ivan Vanko, Natasha fought her way through Hammer Industries. She found Vanko's computer and quickly released Rhodey's armor from Vanko's control.

THE AVENGERS

Tony overrode the PA system on the Quinjet Natasha was flying and asked her if she missed him before flying in to help Steve Rogers fight Loki. Natasha and Tony later fought alongside each other during the Battle of New York.

AGE OF ULTRON

The two fought alongside each other to retrieve Loki's scepter and in the subsequent battles at the salvage yard and in Sokovia.

CAPTAIN AMERICA: CIVIL WAR

Natasha and Tony sided together on the Sokovia Accords, though for different reasons; Tony believed that the Accords were morally correct, and Natasha simply wanted to keep the team together. They later fought at each other's side at the Leipzig-Halle airport. Natasha, however, betrayed her team in the end and allowed Steve and Bucky Barnes to escape.

Later, at the hospital where James Rhodes was being treated for his paralysis, Tony and Natasha talked with each other. He gave her a halfhearted warning that the government would be coming after her, but denounced their friendship due to her betrayal. The two parted on unpleasant terms.

Quotes
"Agent Romanoff. You miss me?"

- Tony

Fandom
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WIKIS

Trivia

 * In her report on Tony for the Avengers Initiative, Natasha writes "Mr. Stark displays compulsive behavior...prone to self-destructive tendencies. Textbook narcissism."