|“||The vile Black Viper has come from deep space to finish what Red Falcon started. And she did not come alone.||„|
|~ Operation C instruction booklet|
Black Viper is an unstable biomass, thus she can mutate repeatedly, making her more dangerous in the process.
She has three known forms. Her first form is fought at the end of Operation C. The mechanical boss guarding her must be defeated prior to confronting her as the final boss, a mere unprotected cell contained within a glass tube.
Two other forms of Black Viper appear in Contra 4: The first, as a praying mantis-like monster. Once defeated, the creature plummets into a pile of rotting corpses and reemerges as a gargantuan monster. The hero makes an opening on the back of her abdomen with their weapon and the stage continues inside her body until they reach the final battle. Inside her head, above the Earth's atmosphere, the player must take out her eyes and fight her final form, which actually resembles that of Emperor Demon Gava.
First invasion attempt
Black Viper initially comes to Earth and takes over an unnamed nation. She brainwashes its military forces in order to take over the world. The government sends Mad Dog and Scorpion to fight them. The two Contras invade the nation, fight through their defenses and defeat the cyborg who was in charge of protecting her.
They discover that Black Viper was just a large alien cell contained inside a liquid vial. They destroy it, putting an end to her plans for the time being.
Two years after the Alien Wars, Black Viper returns. This time, she controls the remains of Red Falcon's forces and starts a new attack on Earth. At this point, she has evolved into a mantis-like monster. The government picks up a signal from the Galuga Archipelago. They send Contras Bill Rizer and Lance Bean to assist Mad Dog and Scorpion. All of them head toward the island to annihilate Black Viper.
Black Viper is found at a harvest yard on the island. She buries herself into a pile of corpses and reemerges as a colossal alien. The Contras manage to blow up the alien's abdomen and climb through inside her infested hive-like body, heading toward the skull, where her Gava-like form resides. The brain is destroyed and Black Viper permanently dies.
- In the English instruction booklet for Operation C, Black Viper is referred to as a male and no information is given about her being a sibling of Emperor Demon Gava. However, with the release of Contra 4, which is based on the Japanese canon that was adapted into the English localization of the series, the game's producers integrated elements of the American localizations of the older games, thus fusing the two versions together and officially stating Black Viper to be both female and Gava's sister.
- In Contra: Return, there are section alien bosses which strikingly resemble Black Viper's first form.