The evidence is building that Aubrey Plaza is in fact playing the avatar of Death in Agatha All Along. Looking back, it’s hard to believe the MCU was every wary of embracing Marvel Comics’ more fantastical side. Gone are the days when Thor teased that he came from a place where science and sorcery were one and the same thing; now, we have gods and monsters, cosmic beings like the Living Tribunal and Eternity, and so much more. But has Agatha All Along actually introduced the avatar of Death?

https://screenrant.com/rio-vidal-lady-death-sharon-death-theory-explained/