Ever since Marvel Studios' very first MCU-set Disney+ series, WandaVision, led to speculation that Mephisto might be behind the strange goings-on in Westview, there have been rumors relating to the demonic villain making his debut in a future show.
Last year, we finally got confirmation that Mephisto will factor into the Irohheart series, but rumor had it that he may also show up in Agatha: Coven of Chaos, with several online scoopers claiming that he'd be introduced as a long-time ally-turned-enemy of Harkness' coven.
However, @CanWeGetToast has now refuted these reports, claiming that Mephisto won't appear in the WandaVision spin-off, but will be referenced via Agatha's son Nicholas Scratch.
Even if Mephisto doesn't show up, it sounds like there'll be plenty of other problems for Harkness to contend with, including her ex Rio Vidal (Aubrey Plaza) and Salem's Seven.
Coven of Chaos will focus on powerful witch Agatha Harkness, who almost managed to defeat the Scarlet Witch (Elizabeth Olsen) in the season finale of WandaVision before being bested and trapped in Westview in her "nosy neighbour Agnes" persona.
Though Olsen is not expected to appear, there's speculation that Wanda might have something to do with Harkness' release and/or reformation following the events of Doctor Strange in the Multiverse of Madness.
Jac Schaeffer, who is under a joint overall deal with Marvel and 20th Television, will serve as writer and executive producer and will also helm multiple episodes along with Gandja Monteiro (Wednesday; The Chi) and Rachel Goldberg (Cloak & Dagger; Mayans M.C.)