I created some retcons that weave together the origin and trajectory of the Darkhold in the MCU, aligning the origins and wielders seen throughout Marvel Television and Marvel Studios productions, filling in plot gaps and making the Darkhold we see the same artifact across all appearances.
Eras ago, the demon Chthon, hailing from the Dark Dimension, created the Darkhold Castle atop Mount Wundagore as a fragment of the Dark Dimension on Earth and inscribed the writings on the castle’s walls to produce the Darkhold, the Book of the Damned. This explains why in Agents of S.H.I.E.L.D. it is believed the book comes from the Dark Dimension: because the castle itself is part of that dimension manifesting in the earthly plane.
The book acquires a degree of sentience, altering its form, design, and abilities over time to deceive its wielders and those who seek it. This explains the difference in design between Marvel Television and Marvel Studios, as well as why in Agents of S.H.I.E.L.D. the writings appeared in the bearer’s native language, while in later productions this was not the case.
During the Middle Ages, Morgan le Fay came into possession of the Darkhold and was corrupted by it. In one of her battles with King Arthur, Morgan was gravely wounded and on the brink of death. To save herself, she cast a spell binding her own life to the Darkhold. This is why she would later claim that the book was hers and part of her, even being able to sense when it was stolen.
Time passed and many attempted to steal the Darkhold from Morgan, but unsuccessfully, until in the 18th century Morgan engaged in a magical battle against the witch Agatha Harkness, who hungered for power. Agatha banished Morgan to the Dark Dimension and took the Darkhold for herself, growing ever more powerful.
At the end of the 20th century, Agatha was attacked by Ulysses Bloodstone during his Crusade Against Monsters. Though too powerful to be killed, Ulysses managed to wrest the Darkhold from her and, using the Bloodstone, cast a spell that prevented Agatha from accessing the book for as long as she lived. Agatha was forced to remain apart from the book, which was soon taken from Ulysses by Johnny Blaze, wielder of the Spirit of Vengeance, who hid it in the basement of his home.
In 2012, the Darkhold was discovered by Joseph and Lucy Bauer, and later, in 2017, we see the events of season four of Agents of S.H.I.E.L.D., where the book is used by various individuals such as Eli Morrow, Aida, and Holden Radcliffe. In the end, Robbie Reyes opens a portal to Hell to return the book. However, since Hell is but one of the dimensions within the Dark Dimension, Robbie is in fact returning it to its original place: the Darkhold Castle on Mount Wundagore, as the castle itself is a fragment of Hell on Earth. Moreover, the snowy mountainous landscape visible through the portal matches Mount Wundagore.
In 2018, Nico Minoru releases Morgan le Fay from the Dark Dimension. Upon returning to the earthly plane, Morgan reclaims the Darkhold at the castle. We then have the events of season three of Runaways, where Morgan is once again banished to the Dark Dimension and the book is entrusted to Nico Minoru, who protects it to prevent further corruption.
However, the Snap occurs and Agatha Harkness is among the victims. With her death, the spell cast decades earlier that prevented her from accessing the Darkhold is nullified, as she is no longer alive. In 2023, the Blip reverses the Snap, and Agatha, resurrected and now free from the spell, defeats Nico Minoru and reclaims the Darkhold for herself.
After this, we then have the events of WandaVision and Doctor Strange in the Multiverse of Madness, in which Wanda, by destroying every copy of the Darkhold across the Multiverse, also indirectly kills Morgan le Fay, since her life is bound to the book.
