Scarlett Johansson finally closed out Natasha Romanoff's Marvel Cinematic Universe story in ‘Black Widow’, but there were also other heroes the actor could've portrayed. ‘Black Widow’ first entered the MCU in 2010's ‘Iron Man 2’, making an immediate impression by flipping ‘Happy Hogan’ (Jon Favreau) and getting hired as Tony Stark's (Robert Downey Jr) assistant. But, of course, she was simply undercover and keeping an eye on Stark at the time. Over the next decade, Johansson brought Natasha Romanoff/’Black Widow’ to life as a vital member of the ‘Avengers’. She saved the world several times and ultimately gave up her life to reverse Thanos' (Josh Brolin) deadly finger snap in ‘Avengers: Endgame’.
Other actors were also considered for ‘Black Widow’ before Johansson signed on. According to rumors, Natalie Portman, Jessica Biel, and Jessica Alba were all possibilities for the role. However, Emily Blunt perhaps came closest to portraying Natasha Romanoff in the MCU. Unfortunately, the actor revealed she had to turn down the role of ‘Black Widow’ due to contractual obligations to ‘Gulliver's Travels’. However, she didn't want to do ‘Gulliver's Travels’ and later called the decision a bit heartbreaking.
Though Johansson ultimately took on the role of ‘Black Widow’, there were other options on the table. In the new Marvel Studios book, ‘The Story of Marvel Studios: The Making Of The Marvel Cinematic Universe’, Johansson revealed her other choices for MCU hero. "I brought up some of the characters that I had researched that I thought could have some space in the universe," she said. Those other options were Wasp or Blonde Phantom. Of course, ‘Black Widow’, the character she ultimately played, was also on Johansson's list. However, the other characters would've presented exciting options.
Blonde Phantom could've worked perfectly in place of Black Widow's MCU timeline. In Marvel's comics, Blonde Phantom is like a gender-swapped version of ‘Superman’. She's a reserved secretary who takes off her glasses and lets her hair down to become a masked superhero. Since Natasha Romanoff entered the MCU by pretending to play Tony Stark's assistant in ‘Iron Man 2’, substituting Blonde Phantom would've been an easy transition.
Wasp is more of a surprise as a ‘Black Widow’ replacement. In Marvel's comics, the character is one of the founding members of the ‘Avengers’, so the hero could fit in seamlessly with the MCU's story. However, Marvel had early plans to make a Zooey Deschanel version of Wasp include a lot of humor. ‘Black Widow’ is one of the most serious members of the Avengers and has one of the darkest backstories. -Screen Rant