The Doctor Strange 2 ending left us with a lot of unanswered questions, with new sorcerer Clea (played by Charlize Theron) arriving from the Dark Dimension to tell Strange that his multiverse-hopping had dire consequences: and it was up to them to go fix it.
His third eye also makes an appearance as a result of meddling with the Darkhold. In an interview with ComicBook about the ending, screenwriter Michael Waldron said, “That’s the bill coming due. As Wong says, ‘You used the Darkhold to possess your own corpse.’ Surely, there must be some fallout.”
He added, “It was a little bit of a throwback to [Sam Raimi’s] old Evil Dead, and that groaner of an ending, or it’s just like, ‘Oh my God, things turned out bad in the end.’ So, yeah. We’ll see what all that means for Stephen.” Although we get a hint of a darker Stephen Strange in the final moments of the MCU movie, Waldron revealed in the film’s Disney Plus commentary that, at one stage, things were set to get a lot darker.
One alternate ending involves Sinister Strange, who we meet after he destroys his own reality trying to be with Christine, making his way to Earth-616.
“Strange gets trapped in that [incursion] universe… and then [Sinister Strange] turns around, and the third eye opens.” According to Waldron, the twist ending would have been accompanied by the laugh of horror movie legend Vincent Price (yes, just like in Michael Jackson’s Thriller!).
Unfortunately, this didn’t happen, with Sinister Strange being decisively dead after fighting with Earth-616’s Stephen — but who knows what other Doctor Strange variants are out there?