Warning! This article contains SPOILERS forFantastic Four: First Steps #1!
Marvel’s officialThe Fantastic Four: First Stepscomic prelude drops a major reveal about the team’s MCU origin. Matt Shakman’sThe Fantastic Four: First Stepsglosses over the titular team’s early days in order to focus on their fight against Galactus. However,the Fantastic Four’s MCU prelude comicbriefly revisits the mission that gave the MCU’s First Family their famous powers.
Fantastic Four: First Steps #1, written by Matt Fraction, explains that the Fantastic Four’s space mission is a huge public event in their universe, and unlike Fox’s 2005 movie, the team develop their powers as soon as they return to Earth. They also rush to a period of quarantine where they get acquainted with their abilities.

Most importantly,Fantastic Four: First Steps #1makes a drastic change tothe origin of the Fantastic Four’s powers, which is traditionally attributed to cosmic rays.
The Fantastic Four: First Steps' Comic Prelude Suggests The MCU Made A Huge Change To The Team’s Lore
Fantastic Four: First Steps #1; Written by Matt Fraction; Art by Mark Buckingham
Rather than Marvel’s traditional cosmic radiation,Fantastic Four: First Steps #1reveals that the heroes are"bombarded in a blaze of celestial radiation.“While this could be a different way to describe cosmic radiation, the mention of “celestial” strongly suggests that the MCU’s Fantastic Four are connected to Marvel’s Celestials. It could be a simple wording change, but it might also have huge implications on MCU lore.
Traditionally, cosmic rays are a unique type of radiation in the Marvel multiverse.Cosmic radiation is the inverse of Gamma radiation, which earns it the name “Anti-Gamma”. As such, it only awakens superpowers in a select group of characters, while it’s deadly to others. Marvel Studios might be making some tweaks in order to tie it closer to the Celestials.

In Marvel Comics, the Leader combines cosmic radiation with Gamma radiation to transform Thaddeus Ross into the Red Hulk.
The Celestials created the Eternals and provided them with a wide assortment of powers, making them the earliest known superheroes. It has also been repeatedly implied thatthe Celestials added genetic traits to human beings, allowing them to develop superpowers once awakened. These traits include the X-Gene, but also the foundations for other abilities that activate with different external factors, such as the Fantastic Four’s cosmic radiation shower.

The Fantastic Four: First Steps' Comic Prelude Suggests Eternals Is Still Relevant To The MCU
The Celestials Are Still Key In Phases 5 & 6
Marvel’sEternalswasn’t as well-received as the studio planned, and its titular heroes have been largely overlooked since their big-screen introduction. However,the MCU has kept the Celestials relevant in the background.Captain America: Brave New Worldrevealed that the Celestials are the first known source of Adamantium, and now,The Fantastic Four: First Stepsmight be revealing that they’re the source of the Fantastic Four’s powers.
While the Eternals are unlikely to receive a sequel anytime soon, the MCU may have solid plans for the Celestials in the near future. The Fantastic Four, the MCU’s next generation of X-Men, and perhaps even the Hulk may owe their origin to the Celestials in the Marvel Cinematic Universe. AfterThe Fantastic Four: First Stepshits theaters, the team’s next MCU appearances will likely provide more information.