WARNING: The following contains spoilers for WandaVision Episode 9, "The Series Finale," now streaming on Disney+.
The final episode of Disney+'s WandaVision confirms that Agatha's spell book is the infamous Darkhold, also known as the Book of the Damned. The book previously appeared in both Marvel's Agents of S.H.I.E.L.D. and the Hulu series Marvel's Runaways, where it served as a major source of conflict. While the Darkhold looks exactly the same in both of these shows, the book in WandaVision looks completely different. Sadly, this could be an indication that Agents of S.H.I.E.L.D. and Runaways will no longer be considered part of the Marvel Cinematic Universe.
In the two shows produced by Marvel Television, the Darkhold looks and operates in the exact same way. It has a pristine, dark red cover with a raised ambigram design that reads "Darkhold" from either direction. Upon first opening the book, the pages appear to be crisp, white, and blank. After a moment, the contents then magically appear in the reader's first language. The book can even translate itself into binary code, like when the android Aida read from it. The Darkhold contains infinite knowledge, but it also tends to corrupt the mind of anyone who reads it.
Conversely, the Darkhold in WandaVision has a much different appearance. The cover is a dark gray and has an image of what looks to be two keys going into opposite ends of a lock. It oozes magic in the form of yellowish, orange light and the pages inside look messy and worn. Although both Agatha and Wanda read the Darkhold, the audience doesn't get to see if the pages magically fill in or if the language differs depending on the reader. It is also unclear if this version of the book also corrupts the reader's mind, which could spell trouble for Wanda in the future. In short, this Darkhold does not appear to be the same book featured in either S.H.I.E.L.D. or Runaways.
This isn't the first time a prop's inclusion has caused discrepancies in the MCU's continuity. After all, the Infinity Gauntlet appeared in Odin's vault on Asgard long before Thanos entered the fray, but it was later revealed as a fake. On the other hand, the Darkhold's altered appearance may not be so easily explained. After it last appeared in Runaways, it is possible that the book was rebound and given a new cover, but this doesn't explain why the pages inside look so different. Since Wanda takes the book at the end of the series, the Darkhold's canonical history might be revised in future Marvel projects to exclude its past appearances.
The connection between Marvel Studios' movies and Marvel Television's shows has been subject to debate for quite some time and WandaVision's new Darkhold certainly seems to be widening the gap between the two. In the beginning, series like S.H.I.E.L.D. and Agent Carter were decidedly part of the MCU canon, taking place within the same universe as the films. As time went on, however, tie-ins became few and far between and the shows went largely unacknowledged in the movies. This led to later projects like Netflix's Defenders and Freeform's Cloak & Dagger sharing little to no connections with the films despite being set within the MCU. Eventually, all of these series were canceled and the ones that continued past the events of Avengers: Infinity War didn't acknowledge Thanos's snap, leading some to believe that the shows were no longer canon.
Now that each series is officially over, Marvel can simply recast these characters and introduce in them in other projects. Nevertheless, it seems a shame to ignore all of the incredible performances and amazing stories from shows like S.H.I.E.L.D., Daredevil, and Runaways. Instead of rebooting these characters, many have been hoping that Marvel Studios will get some of the same actors to reprise their roles while leaving their backstories ambiguous. In this way, Marvel could incorporate elements of the Marvel Television projects into the MCU without having to definitively declare the shows canon or not. For now, audiences will have to just wait and see if Marvel decides to keep the same versions of these characters or give them all a brand new look like the Darkhold.
Written by Jac Schaeffer and directed by Matt Shakman, WandaVision stars Elizabeth Olsen as Wanda Maximoff/Scarlet Witch, Paul Bettany as Vision, Randall Park as Agent Jimmy Woo, Kat Dennings as Darcy Lewis, Teyonah Parris as Monica Rambeau and Kathryn Hahn as Agnes.