Dwarven King Eitri, this enchanted ax can manipulate raw energy from the universe itself. It appears to be bonded to Thor, and just grasping it allowed the God of Thunder to heal at an accelerated rate.
It's generally assumed that the most powerful demonstration of Stormbreaker's power was the moment when Thor threw it at Thanos. Stormbreaker proved capable of resisting all six Infinity Stones; in the final battle of Avengers: Infinity War, Thanos projected a beam attack against Thor, one that flared with the colors of all six Stones, but Stormbreaker didn't even seem to be slowed by the blast.
Related: Everything We Know About Thor's Role In Avengers: Endgame
But here's the interesting thing; when Eitri was explaining just how powerful Stormbreaker could be, he didn't talk about its propensity to resist summon the Bifrost. Otherwise known as an Einstein-Rosen bridge, the Bifrost is a wormhole that can transport a person from one place to another. On Asgard, it took a massive installation to create the Bifrost, but Thor can do it just by holding Stormbreaker. It's an impressive feat, but in truth fans have underestimated its importance.
The first Star Wars. - and that notion directly applies to Thor's Stormbreaker ax, as it, too, has the power to summon the Bifrost.
Stormbreaker truly is the most powerful weapon the MCU has ever seen. Not only can it resist the power of Avengers: Endgame.
