In Kill Bill: Volume 1, the protagonist’s code name is Black Mamba.
The protagonist, played by Uma Thurman, is primarily called the Bride during the film. She is a former member of the Deadly Viper Assassination Squad, an elite group of killers led by Bill. Each member uses a snake-based code name, and the Bride’s is Black Mamba.
The other snake names belong to different characters. O-Ren Ishii is Cottonmouth, Vernita Green is Copperhead, Elle Driver is California Mountain Snake, and Bill is Snake Charmer. “Bride” is the character’s most visible label in Volume 1, but it is not her Deadly Viper code name, which is why the two answers can be easily confused.
The Black Mamba is a real African snake known for its speed, length, and highly potent venom. In the film, the name reinforces the Bride’s reputation as a lethal assassin. Volume 1 follows her recovery from an attempted murder at her wedding rehearsal and her pursuit of former allies in search of revenge.