What name did Beyoncé use for her fierce stage persona on her 2008 double album?

Beyoncé used the name Sasha Fierce for her fierce stage persona on her 2008 double album.

The persona appeared in the album title I Am... Sasha Fierce, released on November 12, 2008. Beyoncé described the two-disc project as contrasting her personal side with the more confident, glamorous, and performance-focused character associated with Sasha Fierce.

The album’s first disc, I Am..., emphasized ballads and more personal material. The Sasha Fierce disc leaned toward energetic dance-pop and R&B performances. Its singles included “If I Were a Boy,” “Single Ladies (Put a Ring on It),” and “Diva.”

Beyoncé later said in interviews that she no longer needed to separate herself from the persona because the qualities associated with Sasha Fierce had become part of her own identity. The name therefore refers to a defined performance persona, not a separate recording artist.