India, Oct. 23 -- Marvel fans may have another reason to worry about Thor's fate in Avengers: Doomsday. With Robert Downey Jr. returning to the Marvel Cinematic Universe (MCU), this time as Doctor Doom, the upcoming film is expected to put Earth's mightiest heroes through one of their toughest battles yet. But amid the excitement surrounding the multiverse crisis, a long-running fan theory has raised an unsettling possibility: could Chris Hemsworth's God of Thunder sacrifice himself to give the Avengers a fighting chance against Doom?

Nothing has been confirmed by Marvel Studios, but details from the film's teaser trailers have given the theory fresh momentum.

Avengers: Doomsday Trailer Fuels Thor Death Theory

The first major teaser fo...