Warning: Contains SPOILERS for Doctor Strange in the Multiverse of Madness.
Doctor Strange's third eye at the end of Doctor Strange in the Multiverse of Madness may not be what it seems, but why does he get it to begin with? Doctor Strange has an extensive variety of magical abilities, ranging from teleportation and spell casting to astral projection and transmutation. However, Doctor Strange's third eye, a tool that the Ancient One only hinted at during their first encounter in 2016's Doctor Strange, had never really appeared in the MCU before the Master of the Mystic Arts' battle against the Scarlet Witch.
The only other character known to possess this eye is Sinister Strange, who got it after using the Darkhold of his universe to Dreamwalk into other realities and kill his multiversal variants. This seems to suggest that the third eye is a direct consequence of using the Darkhold and that the Doctor Strange variant from universe 616 is doomed to go down a similar path. However, it may not be as straightforward as it seems.
Related: Did Marvel Really Just Kill Off That Important Doctor Strange Character?
In the comics, Doctor Strange's third eye is an organic manifestation of the Eye of Agamotto. It represents the wisdom of the sorcerer Agamotto and his fellow Vishanti, allowing Strange to see his enemies' true intentions and break magical illusions. Doctor Strange's third eye is originally a sign of a higher level of consciousness, and it can only be used by those whose souls are devoid of corruption. However, the third eye might also entail the complete opposite within the MCU. Doctor Strange's third eye appeared on his forehead involuntarily not long after using the Darkhold, which corrupts any being that uses it,
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