Agatha All Along episode 5 is hiding another major clue in plain sight about the real identity of Aubrey Plaza's Marvel witch Rio Vidal

Warning: This article contains spoilers for Agatha All Along episode 5.

There are a whole bunch of unresolved mysteries in Agatha All Along – just who is teen is what’s going on with Nicolas Scratch , and who is Rio Vidal really? Well, while the latest episode has cleared up a bit more about Teen and Nicolas Scratch, there’s also a small detail to help with unlocking Rio’s identity too.

Episode 5, ‘Darkest Hour / Wake Thy Power’ sees the coven face their next trial: confronting Agatha’s past. The premise is pretty simple it seems, they must work together to communicate with the dead using a Ouija Board.

After a botched first try, the coven try again as the spirit confirms who they are. When the word "death" is spelled out, everyone looks suitably shaken, apart from one character: Rio. She beams and throws her head back laughing. Suspicious, right?

It seems to be another indication that Rio is actually a major comic book villain in disguise: Lady Death . In the Marvel comics, she’s considered one incarnation of Death, and has rubbed shoulders with several of the biggest comic book baddies around, including Thanos. Her reaction to Death’s name is pretty intriguing then, even if the spirit turns out to be Agatha’s mother.

There was another indication back in episode one too, when it was spotted that Lady Death was pictured in some tarot cards with a knife. Rio was then seen holding the exact same knife not long after…

This isn’t the only suspicious thing that Rio does in the latest episode either, as when the coven completes the task and heads back to the Witches' Road , she is nowhere to be seen. We’ve got our eye on you Rio.

For more on Agatha All Along, check out our Agatha All Along review , our Agatha All Along release schedule , and our guide to all the upcoming Marvel movies and shows .