According to the book, the MCU was created in a Big Bang-type phenomenon 13.8 billion years ago. It takes billions of years for life to form and evolve, which results in a life-or-death struggle “defined by an innate sense of morality that many sentient beings possess — to protect themselves, but also others.” It is from this cosmic melee that superheroes emerge, powerful figures who live by a highly principled code.
In terms of the timeline, there are three significant events. The first is “The Handiwork of Celestials.” These entities are considered the “most powerful forms of life to ever exist.” They are capable of creating suns that support a myriad of galaxies throughout the universe.
Next is “Ego Takes Shape.” You know Ego from “Guardians of the Galaxy Vol. 2.” He’s Peter Quill/Star-Lord’s father, and assumes the form of Kurt Russell because, let’s face it, if you had the power to dictate your human appearance, you’re choosing the star of “Big Trouble in Little China” and not looking back. In actuality, Ego is a Celestial who, rather than become a colossus like his fellow entities, decided to transmogrify himself into a sentient planet. That’s a choice. Personally, I’d throw all my elemental energy into being Kurt Russell, but different strokes and whatnot.
Which brings us to the most pivotal moment in the history of the MCU to date.