With Thor and Rocket Raccoon's help, Eitri reignited the dying star and re-lit the forge, melting down ingots of Uru and pouring it into a mold. He then shattered the mold, revealing the axe's blade and weight, but misplaced the handle for the weapon. Seeing that Thor was close to death after taking the burnt of the dying star's 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 the smoking husk of Thor, who used its power of the Bifrost to go forth to Wakanda and assist his fellow Avengers.
Stormbreaker was used in the Battle of Wakanda to great effect, augmenting Thor's own lightning massively. It was, notably, the only weapon that caused any noticeable harm to Thanos during the entire conflict: Thor impaled Thanos using it just after Thanos completed the Infinity Gauntlet; however, he intentionally aimed for the chest instead so he could gloat to Thanos, resulting in Thanos only being badly injured rather than instant killed. This proved to be a fatal mistake as the blow could not stop Thanos from activating the Infinity Gauntlet, thus wiping out half the life in the universe before escaping, with the wound closing soon after upon Thanos activating the Gauntlet.
Like Mjølnir before it, Stormbreaker will return to Thor's hand when summoned, and strikes his opponents with massive force. It glows 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 seamlessly while using it, unlike Mjølnir, which required the user to spin it at great speed to lift them off the ground.
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 that came before it. Eitri even went as far as to say Stormbreaker is the strongest weaponry in Asgard's history. As a weapon designed to kill Thanos, it is one of the few able to harm and injure him, with Thor managing to inflict considerable pain and injury when he pushed the axe deeper into the Titan's chest. Thanos himself, mocking Thor for failing to prioritize a killing blow, suggested that a strike to the head would have killed him outright. It is so powerful that when charged to Thor's full power, it was capable of overtaking the completed Infinity Gauntlet, quickly slicing through the beam unleashed upon Thanos.
- 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
- When asked how can Stormbreaker overpower the power of the completed Infinity Gauntlet, writers Christopher Markus and Stephen McFeely suggest that Eitri is responsible because of his "Dwarven magic": He made both items and made it so that Stormbreaker is able to defeat the Infinity Gauntlet.