Doctor Strange in the Multiverse of Madness

Wanda attacks Kamar-Taj to capture America Chavez. After learning that Chavez possesses the unique ability to travel through the multiverse, Wanda demands the sorcerers surrender the girl. When Doctor Strange refuses, Wanda launches a brutal assault, killing numerous sorcerers because she believes Chavez's powers are the key to reaching her children Billy and Tommy, whom she created during her time in Westview.

Wanda's transformation into the Scarlet Witch was foreshadowed when she sought out the Darkhold, a corrupt tome that preys on users' desires.

Wanda became the Scarlet Witch after acquiring the Darkhold, a sinister mystical tome that corrupts its users by amplifying their deepest desires. The Darkhold twisted Wanda's grief over losing her children in Westview into an obsession to reunite with them. This corruption awakened her chaos magic and transformed her into the powerful Scarlet Witch, who then embarked on a multiversal quest to find versions of Billy and Tommy.

Wanda's turn was hinted at when she struggled with grief after Westview and began researching dark magical artifacts.

The Darkhold is an ancient corrupt mystical tome, often called the Book of the Damned. It corrupts anyone who reads it by exploiting their deepest desires and transforming them into darker versions of themselves. The Darkhold enabled Wanda to dream-walk across universes and contains the power source of Mount Wundagore. It is the direct opposite of the Book of Vishanti.

The Darkhold's corrupting influence was established in earlier Marvel properties, where it corrupted Agatha Harkness.

The Illuminati of Earth-838 executed their Doctor Strange because his reckless use of their universe's Darkhold nearly caused a catastrophic "incursion", an event where two universes collide and destroy each other. After Strange used the Book of Vishanti to eliminate Thanos, the Illuminati decided to kill him to prevent any future multiversal catastrophes that his actions might cause.

Earth-838's Strange was shown seeking the Book of Vishanti, indicating he had already been using dangerous dark magic.

Dream-walking is a dark magical technique that allows a person to project their consciousness into their variant in another universe, essentially possessing that universe's version of themselves. Wanda uses the Darkhold to dream-walk into her counterpart on Earth-838, who lives a peaceful suburban life with her children. This ability allows her to physically interact with other universes while remaining connected to her original body through the Darkhold.

The Darkhold contains ancient dark magic spells, and Wanda's growing power made such multiversal travel possible.

America Chavez is being hunted because she possesses the unique ability to travel through the multiverse by punching open portals. This power manifests only when she experiences extreme fear, making it difficult for her to control. Both the demon and Wanda Maximoff pursue her because capturing her would grant them unlimited access to travel between universes, which Wanda wants to use to reach her children.

The movie opens with Chavez's abilities being demonstrated as she flees a demon in the void between universes.

The Book of Vishanti is a mystical tome that serves as the ultimate source of light magic and the direct opposite of the Darkhold. It contains the power to defeat any threat in the multiverse, which is why both Stranges sought it. The Illuminati used it to defeat Thanos in their universe, while the variant Strange died trying to obtain it to fight the demon pursuing Chavez.

The Book of Vishanti was established as a powerful artifact in earlier Marvel properties, representing pure magical energy.

America Chavez defeats Wanda by finally gaining control of her powers. Doctor Strange inspires her to stop fearing her abilities and embrace them. When Wanda attempts to seize Chavez's powers, Chavez uses them to transport Wanda to Earth-838, where her children witness her threatening form and recoil in fear. This confrontation causes Wanda to realize the horror of her actions and choose redemption over conquest.

Chavez's powers only activate when she's afraid, so learning to control her fear was always the key to unlocking her full potential.

Wanda sacrifices herself after seeing her children's fear of her, which breaks through the Darkhold's corruption. Realizing the harm she's caused across the multiverse, she uses her powers to collapse Mount Wundagore, destroying all copies of the Darkhold everywhere and preventing anyone else from being corrupted by it. This act of redemption costs her own life but ends her reign of terror.

Wanda's maternal love was the very thing the Darkhold exploited, so confronting that love directly was the only way to break its hold.

The third eye that Doctor Strange develops represents the lingering corruption from his use of the Darkhold. Even though he used it to dream-walk and save Chavez, the Darkhold left a permanent mark on him, symbolizing that his exposure to dark magic has fundamentally changed him. This sets up future storylines as hinted by the mid-credits scene about an impending incursion.

Strange's use of the Darkhold, even for heroic purposes, was established as dangerous given what happened to Wanda.

The incursion is a catastrophic event where two universes collide and destroy each other. In the mid-credits scene, a mysterious sorceress warns Strange that his actions, specifically using the Darkhold and dream-walking, have triggered an incursion that he must help fix. This sets up future multiversal conflicts and suggests Strange's choices will have far-reaching consequences across the Marvel Cinematic Universe.

Earth-838's Illuminati specifically warned that Strange's reckless use of the Darkhold could cause incursions, and their prediction comes true.