Shang-Chi and the Legend of the Ten Rings may have secretly solved a WandaVision post-credit scene mystery that's left Marvel Cinematic Universe fans baffled. In Shang-Chi, Simu Liu's titular character tries to move on from his past, hiding in San Francisco from his old life as an assassin. But, unfortunately, Wenwu (Tony Leung), his criminal father and the leader of the Ten Rings, orders his terrorist group to attack his son. Thinking his estranged sister, Xialing (Meng'er Zhang), could also be in danger, Shang-Chi heads to Macau to find her. Ultimately, the film reveals that Wenwu was pulling strings behind the scenes and wants his children to join him in saving their mother, Ying Li (Fala Chen). A former guardian of the mystical dimension of Ta Lo, Ying Li died when Shang-Chi was just a child, so he has doubts about his father's plan. In the end, it turns out the soul-sucking Dweller-in-Darkness was manipulating Wenwu to think that his wife was still alive, and the family has to face off against the dark entity and its minions.

WandaVision is all about Wanda Maximoff (Elizabeth Olsen) finally taking her place as Scarlet Witch. In the series, Wanda deals with the loss of Vision (Paul Bettany) by creating a fake sitcom world and enslaving the residents of a small town to play different parts in it. However, Wanda's sitcom world also brings some uninvited guests. Kathryn Hahn's Agatha Harkness arrives to try to steal Wanda's Chaos Magic away from her, but her evil scheme backfires. Eventually, Wanda embraces her role as Scarlet Witch and becomes one of the most powerful characters in the MCU.

Related: Shang-Chi's Ten Rings Can Make Him Fit The Avengers' Most Powerful Team

WandaVision reveals a mystery in a post-credit scene, and Shang-Chi may solve it. In a WandaVision credit scene, Wanda reads from the Darkhold, a powerful magic book, and hears the voices of her children. Of course, her children disappeared with Wanda's fake sitcom world, so the scene was a surprise. However, according to a theory (via Reddit), Shang-Chi clears up what's going on. In Shang-Chi, the Dweller-in-Darkness mimics Ying Li's voice to manipulate Wenwu. The theory speculates that another dark entity, such as Nightmare, is doing the same to Wanda. With Wanda set to appear in Doctor Strange in the Multiverse of Madness and rumors that Nightmare will also appear in the film, the theory seems to hold some weight in the MCU.

Wenwu in Shang-Chi and Scarlet Witch in WandaVision

Shang-Chi isn't imitating WandaVision by accident. Wenwu and Scarlet Witch hearing their loved ones' voices are incredibly similar moments. At the very least, Marvel wants to put the idea in fans' minds that Wanda could be getting manipulated. After all, Wanda hears her kids' voices while reading from the Darkhold, Marvel's most dangerous magical book. The Dweller-in-Darkness contacts Wenwu because he has the power to release the monster from its prison. Scarlet Witch would presumably have enough power as well. Since Shang-Chi and WandaVision both occur after Avengers: Endgame, the Dweller-in-Darkness itself could've been trying to contact Wanda.

Still, there are other options. With Marvel releasing the Multiverse onto the MCU, there are now endless possibilities. In all likelihood, Wanda's kids exist in different timelines. So Scarlet Witch could be tapping into those other worlds in WandaVision. Additionally, Doctor Strange 2 went through a director change, with Sam Raimi taking over the film. Since rumors claimed Nightmare would appear in the movie before that change, the villain's appearance in the Doctor Strange sequel is doubtful. Though Shang-Chi and the Legend of the Ten Rings hints that something is tricking Wanda, Marvel fans could genuinely be the ones getting manipulated.

More: Shang-Chi's Ten Rings Will Return In Armor Wars - MCU Theory Explained

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