A new sorceress appears in the post-credits scene of Doctor Strange 2

After the credits of Doctor Strange in the Multiverse of Madness, a woman in a violet outfit appears on the street. She addresses Stephen Strange, asking him to prevent the destruction of her reality. She then opens a portal that leads them to a dimension reminiscent of the Dark Dimension from the first film.

This character, named Clea, possesses magical powers and is portrayed by Charlize Theron. In the comics, she is the daughter of Prince Orini, the legitimate heir of the Dark Dimension, and Umar, sister of Dormammu. Her presence opens the door to new magical storylines in the MCU.

Source: Screen Large