Mockingbird

Mockingbird (Barbara "Bobbi" Morse) is a special S.H.I.E.L.D. black-ops agent.

Biography
Mockingbird accompanies Hawkeye, and Black Widow during their mission to capture the Hulk, acting as the pilot for their prison transport. After the helicraft is damaged by falling debris, the Hulk saves Barbara's life by catching the transport before it can crash into the ground. This action ultimately leads Hawkeye to believe that the Hulk isn't the monster that he appears to be.

After Hawkeye left S.H.I.E.L.D. and joined the Avengers, Mockingbird replaced him in the black ops team.

Later, she partners with Hawkeye on his mission to track down H.Y.D.R.A. and capture Black Widow. She was sent to keep an eye on the team by S.H.I.E.L.D. higher-ups. Believing it to be the best way to infiltrate H.Y.D.R.A., the two heroes allow themelves to be captured and are brought bound and gagged before Black Widow and her cohorts, including Madame Hydra and Baron Strucker. After freeing herself and helping Hawkeye defeat and capture the villains, Mockingbird boards the S.H.I.E.L.D. Helicarrier, where she examines Madame Hydra with Nick Fury, discovering that she's actually a Skrull posing as Madame Hydra.

At some point after this she was replaced by Veranke.

Power and Abilities
While she is merely a baseline human, Mockingbird is a incredible hand to hand fighter, capable of holding her own against several HYDRA agents at once. In addition, she appears to be skilled in the use of a twin pair of battle staves, which she can use seperately or as a bo staff for fighting and pole vaulting manuvers. She also appears to have incredible apptitude for hand to hand fighting, as she was able to take Hawkeye's place on SHIELD's special ops team in a very short amount of time.