Marvel has typically depicted Ragnarok, the Asgardian Apocalypse that resets Thor and his fellow gods’ reality, as a localized event. Readers have watched the event destroy Asgard and the deities several times, all without doing much damage to Midgard, aka Earth.
In “What If? Age of Ultron” #3, however, Earth is not spared. After slaying Thor and destroying Asgard, the monstrous serpent Jormungand does not stop. Instead, it targets Earth’s Mightiest Heroes, killing scores of Avengers. Soon only a handful of heroes still live, including Falcon, Shang-Chi, Nick Fury, and Black Widow. The small team decides to take on the world-destroying serpent despite the incredibly bad odds. They will almost certainly die, but at least they’ll go out fighting for humanity.
However, their boldness pays off. By taking the fight to Jormungand, the team ends up in a position to find Mjolnir amongst the rubble the serpent has left in its wake. Without expectation, Black Widow grabs Thor’s abandoned hammer. Defying expectations, Natasha has evidently been made worthy by her time fighting to forestall the end of humanity. She can hoist the hammer skyward and become the new God of Thunder. Combining the power of a god with her gift for strategy and capacity for ruthlessness, Black Widow joins the battle. While the book only briefly shows her efforts, Fury’s narration confirms that the spy turned superhero turned god indeed carried the day, and rather spectacularly at that.