Yet another character in Agatha All Along viewers have quickly decided isn’t who they say they are is Aubrey Plaza’s Rio Vidal. Plaza appears in Agatha’s detective show illusion as a government agent who clearly knows the truth about Agatha, even when the witch herself doesn’t. Once Agatha awakens from her illusion, Vidal reappears as a dark witch intent on killing her. The two clearly have history, and loads of sexual tension, but nobody knows why. In forming her coven, Agatha is told to look for a black heart to fill the role of the green witch that viewers assume is meant to be Vidal, but Agatha refuses.
Despite her relatively short screen time so far, fans already have theories on who Plaza is. The black heart used to represent Vidal has led many to suggest she is actually the comic character Black Heart. Fans are desperate for this one to be true as the character is the child of the demon Mephisto, and everybody wants Mephisto to show up in Agatha All Along. (More on that in a bit.) There isn’t much else to support the theory yet, but dropping the character name is already a pretty big hint that this theory could be true. It isn’t the only theory though. It’s also possible Vidal is Victoria Montesi, a character with ties to the Darkhold and the demon Cthon who created it. An even wilder theory is that Vidal is Lady Death herself, on a mission to claim Agatha, who has fled from death for so long with the aid of her powers. So far we know frustratingly little about Vidal, so any of these could be true—or wildly incorrect—at this point.