Viper (Yost Universe)

Madame Viper, or simply Viper, was one of Baron Strucker's lieutenants in HYDRA. She later joined the Serpent Society.

Early life
Viper's early life is shrouded in mystery, but it is implied that something happened to her, which gave her scars on the right side of her face and made her hate people like Captain America. She eventually joined HYDRA and acted as one of Baron Strucker's trusted right hand lieutenants. During his time, Viper heard rumors of the Serpent Crown, which would give her the power to conquer the world in order to impose their new world order, using HYDRA to seek the crown, but without any success.

Skrull Invasion
At some point in time, she was replaced by a female Skrull who posed as her. The Skrull was captured and discovered by Nick Fury after some time.

After several months in a prison cell on a Skrull spaceship, Viper was freed by Captain America. Together, they freed other prisoners, both villains and heroes, and after facing the Super-Skrull, they stole a shuttle and managed to escape. When Viper and the rest of the prisioners came to the Earth, they fought along the Avengers against the Super Skrulls, more later she and King Cobra were captured by S.H.I.E.L.D.

Serpent Society
The Society tried to break her out, and wound up being trapped underground with Quartermain, Cap and Spider-Man. As the heroes tried to escort the civilians to safety the Society retrieved their members one by one. Despite, Captain America having a weak shield and Spider-Man having run out of web fluid, the Serpent Society was taken back into S.H.I.E.L.D. custody.