Black Widow (The Avengers: Earth's Mightiest Heroes)

Black Widow (Natasha Romanova) was a S.H.I.E.L.D. agent, partnered with Hawkeye. However, she began working undercover as a double agent for Hydra. When Clint realized this, Natasha claimed that he was the traitor, sending him to the Vault. After S.H.I.E.L.D.found that the Black Widow was the traitor, Hawkeye attempted to take Hydra down several times. When Hydra waged war on A.I.M., she revealed that she was sent on a mission to spy on Hydra by Nick Fury, who was the only person who knew about the operation. As he was missing at the time, S.H.I.E.L.D. still considered her a threat, so she turned to Hawkeye and the Avengers for help.

She later joined Nick Fury's secret group to hunt down infiltrated Skrulls, and was knocked out by their queen as soon as Fury realized she was impersonating Mockingbird.