The Mandarin
This would make for a very interesting twist (as if we haven’t already had enough of those relating to the Mandarin concept in the Marvel Cinematic Universe), and would enable Marvel Studios to use this character in an intriguing way, without having him as an Iron Man movie villain again.
After the debacle that was Iron Man 3, the Marvel One-Shot All Hail the King revealed that the real Mandarin does actually exist in the MCU – and he’s very annoyed about the version using his name in the third Tony Stark outing.
With that in mind, wouldn’t it be interesting if it were revealed that he was holding one of the last two Infinity Stones? He could even potentially be an accomplice of Thanos in the Avengers: Infinity War movies – and that would be pretty damn awesome.
Now for another hero who might possess one of the last two Infinity Stones.
