Avengers: Endgame was loaded with characters from every corner of the Marvel Cinematic Universe but it almost had one more from Doctor Strange's pocket of the world. In the sequence which brought the Avengers heroes back to 2012 to try to retrieve Infinity Stones from the Battle of New York, the Ancient One was seen on a rooftop helping with the fight. There, she would meet Bruce Banner and talk with him about why she can't give him the Time Stone which the sorcerers are sworn to protect. In the sequence which called for a timeline to be visually explained to Bruce, there was originally planned to be a cameo by Doctor Strange villain Dormammu.
When the Ancient One brings the timeline demonstration to life, she removes the Time Stone and a dark branch reality appears. In the original version of the script which is now available on line for Awards considerations, the camera zooms into the darkened tunnel of that branch reality and is transported to Hong Kong. There, people are running with the camera flying over the crowded street and it eventually lands on a burning Hong Kong Sanctum. After panning up, Dormammu is revealed, before the scene returns to New York where the Ancient One shows Bruce what the timeline would look like if the other five Infinity Stones were also removed.
The scene is reminiscent of the climax from Doctor Strange which saw the Sorcerer Supreme coming face to face with Dormammu time and time again after a battle on the Hong Kong streets. Ultimately, the Time Stone was used to defeat Dormammu in a time after that of the Battle of New York. This would have demonstrated that Strange would not have been able to defeat Dormammu without the Infinity Stone if the Avengers were to take it away from the Ancient One and not return it.
Ultimately, the scene would not have done much to service the already crowded plot of Avengers: Endgame and any fans in the audience who had not seen Doctor Strange might have been left a bit confused. With Thanos now out of the picture, it seems possible that Dormammu's cameo might have been a tease to remind fans that there is another powerful villain lurking in the Marvel Cinematic Universe, and Dormammu might be the next big threat. For now, we wait and see.
Avengers: Endgame is available now on blu-ray, digital download, and for streaming on the Disney+ streaming service.