I'm Coming For You- Marvel AU

Annika grew up in the mysterious Red Room, the place where the all so famous Natasha Romanoff got trained. Except, back in Russia, she is known by a different name. Natalia Alianovna, one of the most successful assassins the Red Room ever had. One of the few to gain the title, Black Widow, from graduating from the Red Room. But she left that life behind, going to America, and becoming a 'Avenger'. Only problem is, the people who trained her want her back. And they will take whatever they have to.
Here is where Annika comes in. She is the youngest girl ever to graduate from the Red room at the young age of thirteen. As a baby, she was found left by the gates of the building, abandoned. Left with only a first name, they decided to take her in. She grew up there, starting her training much younger than the six year olds that are dropped off. With that start, and simply never knowing anything else, made her much more dangerous than any other girl there. She started missions at six, being able to do more damage because of her younger age.
They found another mission for her, one that was unique from all of her others. She had to befriend the young Spider-Man, and get him to show her the other Avengers. So she could bring the older Black Widow home.

AN: Okay, so I'm gonna say it now, before the story even starts. I am making a separate universe. I won't lie to you, I hated how Infinity War and Endgame went. So, something happened to Thanos after Age of Ultron, like he got murdered by somebody. So that threat just won't come anymore. Just thought I'd let you know.