**** THE FOLLOWING CONTAINS SPOILERS FOR THE SERIES FINALE OF WandaVision AND Marvel’s Agents of SHIELD and Runaways****

If you’re reading this, then it’s too late. Friday’s episode of WandaVision, “The Series Finale,” wrapped up the nine-week episodic journey into Wanda Maximoff’s post-Endgame narrative. The Avenger faced the root of her grief and trauma head-on, accepting not only the fate of her beloved Vision but her destiny in becoming the Scarlet Witch. While this series has finished, we know Wanda’s arc is just beginning.

Marvel Studios has confirmed Wanda will be the focus of Phase Four of the Marvel Cinematic Universe — specifically in the film, Dr. Strange and the Multiverse of Madness. And given what we witnessed in the post-credits scene, Elizabeth Olsen’s (Avengers: Age of Ultron, Captain America: Civil War) Scarlet Witch may become the very threat Kathryn Hahn’s (Mrs. Fletcher, This Much I Know Is True) Agatha Harkness warned about. In the scene, Wanda – in her astral form – is studying the Darkhold. This entity may have been new for a lot of WandaVision viewers. But for diehard comics and long-time Marvel TV fans, the Darkhold is a very familiar source of great but destructive power and obsession.

As described in the episode, the Darkhold is the book of the damned and prophesized on the coming of the Scarlet Witch. It foretold this being was not only more powerful than the Sorcerer Supreme but would also bring about the end of the world. But the Darkhold’s power is more complicated than just detailing the fate of mystic beings.

An article by Syfy noted the Darkhold’s appearance in two previous Marvel TV series: ABC’s Agents of S.H.E.I.L.D. and Hulu’s Runaways. In Agents of S.H.E.I.L.D., which wrapped its seven-season run just last year, the Darkhold appeared in a multiseason arc exploring the supernatural side of Marvel. Its power traversed dimensions and time, endowing its reader with immense knowledge. But much like the ring forged from Mount Doom in The Lord of the Rings, the Darkhold possesses its owner to their most carnal desires.

Viewers of S.H.E.I.L.D. witnessed the Darkhold introduce Robbie Reyes, a good-hearted mechanic whose love for his family made him trade his humanity to become the Ghost Rider. Later, the Darkhold powered a synthetic being named Aida. Much like Vision’s origins, Aida was to be a helpmate to her owner. But the Darkhold’s magic bequeathed her human sensibilities and power beyond measure. Her enhanced human emotions created an alternate universe – another reality – in which Hydra were the victors of the land.

In Marvel’s Runaways, which aired for three seasons, the Darkhold was a book of magic with similar spells to conjure alternate dimensions and timelines. Introduced in the final season, another witch named Morgan Le Fey was harkening its power to enslave Earth to her whim. If the series had continued, we would have seen more exploration of the Darkhold and its power throughout the TV universe as Runaways set up a crossover with Freeform’s short-lived Marvel series, Cloak and Dagger. 

According to Syfy, the storylines of S.H.E.I.L.D. and Runaways are not part of the current Marvel Cinematic Universe (MCU) given they belonged to the previous Marvel TV canon. However, these details of the Darkhold give current fans reason to be excited and wary about Wanda’s trajectory. The ramifications for opening that book could befall our favorite witch to becoming the very villain she didn’t want to be.