New Marvel fan theory could explain what happened to Nicholas Scratch in Agatha All Along – and Rio's true identity, too

There's plenty to wonder about in mystery-filled Marvel series Agatha All Along. Who is Teen? What really awaits the coven at the end of the Witches' Road? What happened to Agatha's son Nicholas Scratch? Well, Marvel fans think they've worked out the latter, with a new theory that could also explain the tension between Kathryn Hahn's Agatha and Aubrey Plaza's Rio Vidal...

In episode 4, which we'll delve into here, so be warned, there's going to be major spoilers from this point onwards.

Agatha and co find themselves facing yet another trial on the Road. This time, Teen accidentally curses them when he plays a recording of Lorna Wu's 'The Ballad of the Witches' Road' backwards, leading them to have to perform the song live to lift it. During the challenge, Teen (Joe Locke) gets wounded, and Agatha's obvious devastation combined with certain other comments, suggest she's starting to believe he could be her estranged boy.

Towards the end of 'If I Can't Reach You, Let My Song Teach You', though, Rio tells Agatha, "That boy isn't yours", while Teen asks her outright what happened to Nick. Now, there's always a chance that Rio could be lying and that Teen doesn't know he's Nick, but there's also a chance that he really isn't him.

Shortly after the episode landed on Disney Plus, one viewer took to Reddit to claim the animosity between Agatha and Rio could be linked to Nicholas' fate. "My theory is Agatha and Rio loved each other but Agatha made a deal with Mephisto for the Darkhold," ITandFitnessJunkie wrote. "Agatha knew there would be a price but didn't know what it was. Mephisto sent Rio to collect on the price, which was her son, Nicholas Scratch."

Other fans echoed the thoughts on Twitter, too, with one tweeting: "Agatha's reaction to Teen "dying" is insane. I feel like Rio took Nicholas's life and that's why she said "don't" looking at Rio because he reminds her of her son."

"We all agree that Rio was doing her job and sacrificed Nicholas Scratch but that also resulted in her gaining the Darkhold, only for Agatha to steal and use its magic to hide from her, right?" wrote another.

A few theories as to Rio's identity have been floating around on the internet since before the show even premiered, which is no surprise given that she's an original creation for the series. Many think she could be working for Mephisto, or the devilish supervillain himself, while others are convinced she's Death. 

Her being Death checks out with the above, especially when you consider a few of her scenes in episode 4. At one point, Agatha quizzes her on why she's joined them on the Road, to which she replies: "I get the pleasure of watching what you do best: kill all the witches around you. You get your power, and I get my bodies."

"Magick, as it does, took the path of least resistance. Ferried the closest, most appropriate candidate down, or up..." she also tells Agatha, as she explains why she appeared when the coven summoned a replacement green witch. Up? As in, she resides in the underworld? Perhaps...

Right at the end of the episode, Agatha and the rest of the coven swap stories about their battle scars. Rio's, it turns out, is more of an emotional one as she tells the group: "A long time ago, I loved someone, and I had to do something that I did not want to do, even though it was my job. And it hurt them." Okay, well, now we're convinced...

Agatha All Along episodes 1 to 4 are streaming now. Ensure you don't miss a thing with our Agatha All Along release schedule. For more on the wider MCU, check out our guide to all of the upcoming Marvel movies and shows or get up to speed with our breakdown of the Marvel timeline.