What stage alter ego did Beyoncé use for the I Am... Sasha Fierce era?

Beyoncé used the stage alter ego Sasha Fierce during the I Am... Sasha Fierce era. She described Sasha as a more confident, uninhibited performance persona distinct from her offstage self.

The 2008 album I Am... Sasha Fierce was structured as two discs: I Am, which emphasized more personal ballads, and Sasha Fierce, which focused on energetic performance songs. The album included “If I Were a Boy,” “Halo,” “Single Ladies (Put a Ring on It),” and “Diva.”

Beyoncé later said that she had retired the Sasha Fierce persona because she felt she had matured beyond needing an alter ego. The name is therefore associated especially with the 2008 album cycle, rather than being her permanent professional name.