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).

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.

Curious why Franklin Richards plays such a key role in The Fantastic Four: First Steps mid-credits scene and how it connects to the Multiverse saga? The powerful child holds abilities that could reshape reality,

Fantastic Four First Steps has the dual pressure of re-introducing the team and setting up Avengers: Doomsday.

As the rest of the Fantastic Four mourn her, Reed puts their son on her chest to say goodbye, and then he miraculously resuscitates her. The parents spend most of the movie worried that Franklin might be some kind of monster like Galactus,