According to a Marvel theory stemming from The Fantastic Four: First Steps, Avengers: Doomsday could replicate Avengers: Infinity War’s opening scene.

In their MCU debut, the Fantastic Four become a Fantastic Five with the arrival of Reed and Sue's son, Franklin Richards. Worries that he might not be "normal" are confirmed in Fantastic Four: First Steps when Galactus recognises that the boy can wield an unlimited energy known as the Power Cosmic (presumably because of the "cosmically compromised DNA" shared by both of his parents).

Robert Downey Jr will be introduced as Doctor Doom in Avengers: Doomsday – but what if he’s not the real Doom?

First Steps director Matt Shakman addresses a big Sue Storm moment in the movie's final act and reveals original plans for Franklin Richards' Marvel Cinematic Universe's introduction.

Doomsday connects to The Fantastic Four: First Steps? A key mid-credits scene introduces a mysterious presence, hints at a growing multiversal threat, and sets up one character’s deeper interest in Franklin Richards.

Franklin Richards is an important character for the future of the MCU – and if it’s faithful to the comics, he’ll be incredibly powerful.

There's a fifth member of Marvel's First Family with a very important role to play... Warning: big spoilers ahead!