So guys, I've red an interesting theory on a french website dedicated to cinema about Multiverse of Madness.
The article theorizes the real villain of the movie might be Cthon. Basically, it points out none of the villains shown in the advertising or the trailers (Mordo, Gargantos, Evil Strange) are big enough to really be the ultimate threat and that Wanda might be the starting cause of all problems (wich fits many rumors about Wanda being the villain and the plot of the movie). In W&V, we learn Wanda practices Chaos Magic and at the end of the series, she gets her hands on the Darkhold.
Now, in the comics, Cthon is an Elder God, the God of Chaos, who was banished from Earth because of how evil and powerful he was but before his banishment, he wrote the Darkhold to leave a trace of his power on Earth and is a practioner of Chaos Magic. To return to the world, he marked Wanda upon her brith, making her the Scarlet Witch, so that, the more Wanda's power was growing and she used the Darkhold, the more Cthon's influence was growing as well, until he could possess her and use her as host to finally get freed from his prison.
This could be a really great idea honestly. First, because Cthon is one of the top dogs in Marvel (even Shuma Gorath is somehow weaker than him apparently) and it would requier a large group of people possessing enormous power to fight his influence (Mordo and trailer Strange could be unwanting allies who would first oppose Strange and the other heroes but end up helping them). Second, it would tie to Wanda's story. We know she practices Chaos Magic, she's the mythical Scarlet Witch possessing incredible power surpassing that of almost anyone, she now has the Darkhold and from what has been shown and revealed about MoM and the end of her series where we hear voices, she will try to find her children in the multiverse and spread mayhem in the process, except the article poses that the voices could actually be Cthon messing with her mind to make her overuse the Darhold and her power until he can possess her.
The plot would be similar to the first Doctor Strange movie (an evil god-like being using a mortal user of Magic to get released onto the world) but in a different way that could serve as a very good backstory for Wanda (as it could be said Cthon somehow manipulated events to lead to her tragic past so she would overuse her Magic) and the origin of her powers and create a big link with the magical side of the MCU.
What do you think about it?