The MCU version of Thor’s Stormbreaker was made to kill him. In the comic world, Stormbreaker was forged by Dwarves and not Asgardians as depicted in the movies and other versions of Marvel lore. It is owned by Beta Ray Bill, a powerful alien warrior who possesses super strength, stamina, and endurance but Thor won it after a battle with his new nemesis Kregga the executioner on an alien planet.
With that being said, the film version has enhanced powers that Mjölnir might lack like summoning blasts of lightning or channeling different regions of energy, and even controlling electromagnetic forces. In fact, in the Marvel Cinematic Universe, Stormbreaker was forged to fight Thanos in The Avengers: Infinity War. But the sole purpose of the Stormbreaker was to neutralize the God of Thunder.
Thor Acquires The Stormbreaker From Eitri
The story arc of The Avengers: Infinity War involves the Avengers trying to stop Thanos from acquiring the Infinity Stones so he can wipe out half of the population of the universe including some Earth Heroes, the Guardians of the Galaxy, and Loki. At first, Thor’s mission was to save his people on Asgard, but after seeing all of them get killed at once by Thanos, his grief is unbearable. So instead of going straight to Earth to reunite with his fellow Avengers, Thor decides to go out of his way to acquire a weapon capable of killing Thanos from Eitri (Peter Dinklage), a master blacksmith in Nidavellir. Luckily for them both, the King sacrifices getting revenge on Hela (Cate Blanchett) by creating Stormbreaker using only hot volcanic lava from Muspelheim and metal from Asgard.
The Battle-Ax’s Origins
In The Avengers, it is Eitri who Thor encounters at the end of his journey in Nidavellir. It was this dwarf blacksmith who had invented and fashioned in secret for many years an exceptionally powerful ax called Stormbreaker. Before completing it, however, he decided to hide the weapon away and let other smiths continue working since no one person should possess such a mighty blade. He left it well hidden from others so that none ever got the chance to obtain it. But on Thor’s return, Eitri sees great potential in him and decides to help him out on his quest against Thanos by allowing him to have Stormbreaker as a king’s weapon and not intended for any single individual alone.
Odin Commissioned The Secret Ax
Although it’s hard to disagree that Odin is finally dead, people can take solace in the fact that there are sure to be several flashbacks from Thor: Ragnarok that could get us closer to knowing if this particular Avengers: Infinity War theory holds water. After all, Eitri has already made an appearance in the 2017 film and the Infinity Gauntlet mold was shown to exist before he forged Stormbreaker. That being said, given its existence before being used for such a dangerous purpose, it would make sense for him to bring up what it was originally intended for at some point after its creation. If he were ever asked about making it in the first place, he may have felt obligated later on to reveal what he knew about it and possibly even learned more along with Thor once Odin passed away. It’s highly unlikely Eitri would have brought up much while they were mourning over their fallen King though.
Fortunately, Thor did not follow Hela’s suit. Because the Avenger has made some mistakes in his past (Infinity War), the God of Thunder seems to have mostly learned from them. He isn’t craving power (though it is nice to see him at peace on Asgard). In Avengers: Endgame, we’re able to see just how far he’s come when he sacrifices himself knowing that now isn’t his time, but instead passing the mantle to someone who will do right by the people of Asgard and Earth and move forward as the God of Thunder!