Stormbreaker was designed by the dwarves of Nidavellir to be the greatest weapon in Asgard's history, designed for their king and capable of summoning the Bifrost Bridge on its own. However, it was never forged, and the dwarves had been rendered all but extinct.
In 2018, Thor, Rocket Raccoon, and Groot went to Nidavellir to forge a weapon. Upon arriving, the typically lively forges of Nidavellir were cold and barren, littered with broken parts. Eitri appeared before them and learned that Thor needed a weapon, so he decided to forge Stormbreaker.
With Thor and Rocket's help, Eitri opened the cage around Nidavellir and re-lit the forge, melting down ingots of Uru and pouring it into a mold. He then shattered the mold, revealing the axes' blade and weight, but misplaced the handle for the weapon. Seeing that Thor was close to death after taking the brunt of the power, Groot decided they could not wait for Eitri to find or create a metal handle; he grasped the red hot pieces of metal with one of his arms and then cut the arm off to serve as the handle, truly finishing Stormbreaker. The weapon then revived Thor.
Used by Thor
Stormbreaker was used by Thor to summon the Bifrost Bridge to Wakanda. It was then used during the battle against the Outriders, augmenting Thor’s own lightning massively. It was also used to destroy the Outrider Dropships and the remaining Threshers.
Notably, it was the only weapon to severely injure Thanos by impaling him in the chest soon after the Infinity Gauntlet was completed. However, Thor intentionally aimed for Thanos' chest. This allowed Thanos to activate the Infinity Gauntlet and eliminate half of all life in the universe. As Thanos teleported away in a wormhole, Stormbreaker fell out of his chest and to the ground, covered in his blood.
Residing at the Avengers Compound
Thor then took Stormbreaker with him to the Avengers Compound. Three weeks later, Stormbreaker was summoned to Thor's hand in order to test Carol Danvers's resolve. When she didn’t flinch, Thor smiled.
In 2023, Stormbreaker was used for the first time during the battle against an alternate Thanos. Thor dual-wielded both Stormbreaker and an alternate version of Mjølnir, using them to great effect in the battle. However, Thanos gained the upper hand, catching Stormbreaker when Thor summoned it and nearly forced it into Thor's chest. In the later stages of the battle, Thor used Stormbreaker to battle the combined forces of alternate versions of the Outriders, Chitauri, Sakaarans, and Black Order. At one point, Steve Rogers wielded Stormbreaker, but Thor quickly switched the weapons. After the battle ended, Thor joined the Guardians of the Galaxy and took Stormbreaker with him.
Stormbreaker is able to focus and enhance Thor's powers. Due to it being composed of Uru, the weapon is nigh-indestructible and able to withstand energy blasts created by the Infinity Stones. It is also able to channel dimensional energy and summon the Bifrost Bridge, which enabled Thor to teleport himself, Rocket Raccoon, and Groot to Wakanda.
Like Mjølnir before it, Stormbreaker will return to Thor's hand when summoned and strikes his opponents with massive force. It can glow with an otherworldly blue flame that crackles with electricity and seems to have the ability to home in on a target if Thor wills it. In addition, the weapon allows the user to fly effortlessly while using it, unlike Mjølnir, which required the user to spin it at great speed to lift them off the ground. Unlike Mjølnir, however, the weapon is not enchanted to prevent those deemed "unworthy" from holding it, making anybody with sufficient strength capable of using the weapon. Stormbreaker can also be summoned by those worthy of lifting Mjølnir, as shown when Captain America, who was previously proven worthy of wielding the hammer in his fight against past Thanos, summoned Stormbreaker by mistake some moments later during the Battle of Earth.
Due to its increased size and mass, having both the blade of an axe and the head of a hammer in its construction, as well as sporting an elongated handle enabling the weapon to be wielded two-handed, it is a notably more potent melee weapon than Mjølnir. Eitri even went as far as to say Stormbreaker was meant to be the strongest weapon in Asgard's history. As such, it is one of the few able to grievously wound Thanos, who faced off against the combined might of Doctor Strange, Iron Man, Spider-Man, Drax, Star-Lord, Mantis, and Nebula while suffering nothing more than a tiny scratch on the cheek. Thanos himself mocked Thor for not aiming for his head, indicating Stormbreaker would have been capable of killing him instantly. Being built to stand against the Infinity Gauntlet-wielding Mad Titan, Eitri enchanted it with several properties that allowed it to take advantage of the weaknesses Eitri had installed into the Gauntlet in order to overpower it, quickly slicing through the beam unleashed by Thanos, although that time Thanos was caught off-guard and could have repelled the attack by other means.
It is also capable of healing severe wounds, as shown by it fully healing a sun-damaged Thor.
- In the comics, the Stormbreaker was created by Odin as a weapon for Beta Ray Bill, after he returned Mjølnir to Thor.
Behind the Scenes
- Avengers: Infinity War directors Joe and Anthony Russo explained that the reason Stormbreaker was able to take the brunt of six Infinity Stones was because it has the ability to counteract the powers of the Infinity Gauntlet and because Thanos was caught off-guard, having only realized what that weapon was after he was struck by it. Screenwriters Christopher Markus and Stephen McFeely suggested that because Eitri made both items, he made Stormbreaker to be able to withstand the Infinity Gauntlet.