|Allies|| Captain America|
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.
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. After facing the Super-Skrull, they stole a shuttle and managed to escape. When Viper and the rest of the prisoners 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.
The Society tried to break her out, and wound up being trapped underground with Clay Quartermain, Captain America, and Spider-Man. As the heroes tried to escort the civilians to safety, the Society retrieved their members one by one. The Serpent Society was taken back into S.H.I.E.L.D. custody.
Madame Viper shows to be very hateful to anyone who are against HYDRA. Her scars caused her to have such personality. In desperate times, she was willing to work with her enemies to get things done and remind them that after it's over, she'll resume her hatred again.
Viper was voiced by Vanessa Marshall.
In the Comics
Her real name is Ophelia Sarkissian.
She also goes under the name Madame Hydra.