Fan Casting Widow

One of S.H.I.E.L.D's best agents Natasha Romanoff is sent on a mission to go undercover as a Hydra agent by Nick Fury. While on a mission to deliver inmates from the Raft to the Cube Natasha and Clint are attacked by the Taskmaster who while being undercover Natasha has also become close with. During the fight Nick Fury tells Natasha through her earpiece to switch sides and so he does and goes against Clint. The fight ends with Natasha framing Clint as a double agent and Natasha leaving with Taskmaster. Eventually Natasha leaves Hydra and stops the mission to join the Avengers alongside Clint who still doesn't trust her and stays with the Avengers for a couple of years. Things go pretty smoothly for Natasha until the war between Red Skull and Earth where Natasha meets her end. After a couple of years Natasha is brought back as well as a bunch of other heroes by the East Coast Avengers with the time stone and returns to the Avengers until she dies on a mission to spy on Intelligencia. After a while Clint Barton starts investigating an anonymous person wearing the Ronin suit which no one knows is Natasha who didn't die but was kept as a prisoner by Intelligencia and was turned into a weapon called the Ronin based on Hawkeye's old alias. During the war on Doom she managed to break out of their restraints which led to her teaming up with Yelena Belova and Clint Barton. After the war she went missing again until she and Taskmaster were hired to kill Clint Barton.