The album formally introduces Knowles' alter-ego Sasha Fierce. Knowles said that Sasha was "born" during the making of her 2003 hit single "Crazy in Love". In an interview with Entertainment Weekly magazine, Knowles noted that her alter-ego is "strictly for the stage". The magazine has described it as "the singer's sensual, aggressive alter ego".
Knowles wears a "roboglove" in public to compliment Sasha Fierce. It was Knowles' concept, and New York-based jeweler Lorraine Schwartz made the titanium glove. It consists of several pieces, including a ring, a glove, and a separate component that covers Knowles' upper arm. The glove first appeared in the video for "Single Ladies (Put a Ring on It)". Knowles later wore it on the red carpet during the 2008 MTV Europe Music Awards, on her performance at the Saturday Night Live show, on the cover of Gotham magazine, and in the music video for "Diva".