First Steps culminates with young Franklin Richards facing Doctor Doom himself. Here's why Doom needs Franklin for Avengers: Doomsday.

In Marvel Comics, Doom’s fixation on Franklin is legendary. He views the boy’s near-limitless powers as the key to creating and ruling Battleworld, a twisted reality of his own making as seen in Secret Wars.

First Steps introduces the world to Mister Fantastic, Invisible Woman, Human Torch and The Thing, but there's one other character of importance.

The Fantastic Four: First Steps debuted the most powerful character in the MCU with Franklin Richards, whose powers are almost second to none in Marvel Comics. The newborn was central to The Fantastic Four: First Steps ' plot, which homes in on the family dynamic of the titular team, and he is likely to play a huge role in future MCU installments.

In a 1982 arc by John Byrne, Franklin gets frustrated trying to solve a Rubik’s Cube and uses his powers to age himself into an adult body, though he couldn’t actually gain more emotional maturity. He winds up going back to being a kid, placing restrictions on his own abilities to allow him to have something of a normal childhood.

Franklin’s powers allowed him to create the universe, dimensions, avoid mind control, and every other cool power you can think of. Franklin Richards is considered a Beyond Omega Level mutant, and he is the only one in that category, making him the most powerful mutant on Earth.