It has been announced that the upcoming Marvel film, “Doctor Strange in the Multiverse of Madness,” will feature the return of Benedict Cumberbatch as the titular character. The film’s title suggests that it will explore the concept of the multiverse, which could have interesting implications for Doctor Strange’s character arc. However, there has been speculation among fans that the film may also see Doctor Strange turn evil or become a villain. In this answer, we will explore some possible reasons why this could happen.

Firstly, it is worth noting that Doctor Strange has a complex history in the comics. He has often been portrayed as an anti-hero or morally ambiguous character, and has even turned to the dark side on occasion. This means that there is precedent for the character to go down a darker path, which could be explored in the film.
One possibility is that Doctor Strange could become corrupted by the power of the multiverse. In the comics, the character has often been portrayed as power-hungry and willing to do whatever it takes to achieve his goals. If he were to discover the existence of the multiverse, he may see it as an opportunity to gain even more power and control. This could lead him down a path of corruption, where he becomes increasingly ruthless and dangerous.
Another possibility is that Doctor Strange could be influenced or possessed by a malevolent force from another universe. The multiverse is full of all sorts of strange and dangerous beings, and it is entirely possible that Doctor Strange could encounter one that has the power to take control of him. This would not only provide an interesting challenge for the other heroes in the film, but would also allow for a deeper exploration of Doctor Strange’s psyche and vulnerabilities.
It is also worth considering the events of the first Doctor Strange film. In that movie, we see the character undergo a significant transformation as he learns to master the mystical arts. However, we also see him struggle with his own ego and arrogance, which almost leads to his downfall. If Doctor Strange were to become a villain in the sequel, it could be seen as a natural progression of his character arc. He may have become too powerful for his own good, and his hubris could lead him down a path of darkness.
Another potential reason for Doctor Strange’s turn to evil could be related to the events of “Avengers: Endgame.” In that film, we see the character witness the death of Tony Stark, a close friend and ally. This could have a significant impact on Doctor Strange’s psyche, as he may feel responsible for not being able to prevent Tony’s death. This could lead him to become more cynical and jaded, and could even push him to take extreme measures in order to prevent further losses.
Finally, it is worth considering the broader context of the Marvel Cinematic Universe. The MCU has been building towards a major event known as the “Secret Wars,” which involves the collision of multiple universes. If Doctor Strange were to become a villain in “Multiverse of Madness,” it could be seen as a way to set up this event and provide a major threat for the heroes to overcome.
In conclusion, there are many possible reasons why Doctor Strange could turn evil in “Multiverse of Madness.” Whether it is due to his own hubris, the influence of a malevolent force, or the trauma of past events, there is precedent for the character to go down a darker path. Of course, this is all speculation at this point, and we will have to wait until the film’s release to see what happens to the Sorcerer Supreme.