I just can't express how much I love MCU's Black Widow.
She has a tragic past that regrets everyday and while she knows she can't compensate the loss of everyone she killed, she still feels the need to save as many people as she can because that's the least she can do.
She joined SHIELD for that reason, and became the best agent of them all.
When the moment came, she didn't think it twice before joining the fight to beat, literally, a god and his army of aliens. "This is monsters and magic, and nothing we were ever trained for".
Then she didn't stop when she realized everyone would know her past at the end of TWS. She was ready to face it.
Yeah, she fell in love. And while a lot of people didn't like the relationship between her and Bruce, I think it was very well done. She had reached the point of realization that she could do anything she wanted: avenge the lives of the innocent, be herself and even love someone. She wanted closure and finally live in peace next to someone else.
When she sees that won't be possible, she once again joins the fight. Against a huge army of killing robots.
She defends her way of thinking during CW, but when she finds herself in the wrong side she does what's possible to help her friend. Even if this means becoming a wanted criminal once again.
Now she's coming back into this war. With not much info of what she'll bring to the table, we do see her in the battlefield alongside other people and creatures way more powerful than her. But she's there, brave and ready. She's willing to risk her life because she knows that's the right thing to do.
Even without powers (again, talking about the MCU version), Natasha has definitely become one of earth's mightiest heroes.
And even with Wanda, Sharon, Jessica, May, Daisy, Gamora, Valkyrie and soon Carol, Shuri and Hope... Natsaha is, in my opinion, the OG female bad ass hero.
