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?

Avengers: Doomsday Raises a Big Question About the Fantastic Four How will the Fantastic Four reconcile Franklin Richards’ omega abilities within the established power levels of the MCU?

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

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.