During a Vudu Viewing Party for Avengers: Infinity War, co-directors Anthony and Joe Russo revealed a key difference between Thor's hammer Mjolnir and his new ax Stormbreaker: the latter doesn't require worthiness. That's why Groot was able to lift the ax, not because he was worthy but because he didn't need to be.
Groot picked up the blade. The weapon wasn't finished. It didn't do anything until Thor got his hands on it. Groot was literally holding his own arm up before he cut it off and that became the handle.
Thor's hammer Mjolnir was defined by the fact that only the 'worthy' could lift it – so basically no-one except the god of thunder (and Vision, for some reason). But when it comes to the weapon's replacement, Stormbreaker – which Thor forges in Avengers: Infinity War – Groot is able to lift it too.
Both Mjolnir and Stormbreaker were crafted by the Dwarves of Nidavellir, but Mjolnir was enchanted by Odin and Stormbreaker channels the power of the Bifrost. While Mjolnir required the user to be worthy, Stormbreaker simply requires someone who isn't a mortal to wield it.
The REAL Reason Why Groot Can Lift Thor's Hammer And The Other Avengers Can't
Which is stronger, Mjolnir or Stormbreaker?
Stormbreaker has the additional power to summon the Bifröst, allowing Thor to teleport anywhere in the Nine Realms. Screen Rant has identified Stormbreaker as the more powerful of the two, based on this ability, as well as it being a much larger and edged weapon.
Many viewers have pointed out that Thanos was able to lift Stormbreaker without a problem, but this is because the ax isn't enchanted as Mjolnir is. Others believe Thanos lifted Mjolnir (although briefly) and have even argued that he would be worthy of doing so.
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.
Meanwhile, MCU Phase 4 saw Stormbreaker being wielded by Thor, Gorr the God Butcher, Love, and anyone else who was strong enough to actually lift and swing it. This is because of the respective origins of both legendary Asgardian weapons.
Because it could kill thanos, is more powerful and thor panicked. Had he thought to call Mjolnir thanks would have gone to catch it and it would have knocked thanos on his bottom or something similar. But because thor was reliant on stormbreaker because it was more powerful he did it without thinking.
During a conflict between Beta Ray Bill and Thor, who had been turned into an Herald of Galactus, Bill prevented Mjolnir from returning to its bearer's hand. Seeing no options to reach an agreement, Thor called Stormbreaker and destroyed it by hitting it against Mjolnir.
We're meant to believe that Groot transcends the laws of nature by absorbing wood, acting as a monster with consciousness and generally behaving in manners that do not apply to trees as we know them. Yet Groot's weakness is actually termites.
He can control all plant life via psychokinesis, absorbing it into his body and making himself stronger. He can also extend his limbs and shoot vines from them to wrap around objects and enemies. Should something destroy his body, he can regenerate as long as fragments (i.e. twigs, leaves, etc.)
If Thor decides to use the power of lightning onboard the Asgardian refugee ship to fight the villain and his minions, he may accidentally damage the ship, or worse, even kill his own people. So, he chose to hold himself back, allowing some Asgardians to escape with Valkyrie (Tessa Thompson) and Korg (Taika Waititi).
Turns out, Thanos was taken unawares. He had just incapacitated all the heroes who tried to stop him. And did not see Thor — or Stormbreaker — coming. Or he could have just changed reality and turned Thor into a puddle of water.
In need of a new weapon after the events of Thor: Ragnarok, Thor used the Dwarven forge on Nidavellir to craft Stormbreaker. Due to both the nature of the weapon and Thor's attack on Thanos, Stormbreaker successfully powered through an energy blast from all six stones and dealt a near-lethal blow to Thanos.
How Can Captain America Lift Thor's Hammer? Simple: Steve Rogers is worthy. The inscription on Mjolnir reads “Whosoever holds this hammer, if they be worthy, shall possess the power of Thor.” It doesn't matter how strong you are, if you aren't worthy, you can't lift Thor's hammer, no matter how hard you try.
Unlike the others, Zeus is not worthy to lift Mjolnir, but through a loophole, he can anyway. If Mjolnir is to enter his domain, Zeus's MCU powers should override Odin's enchantment, meaning he can hold Mjolnir. He may not be worthy, but technically Zeus is the fifth character who can lift Mjolnir in the MCU's Phase 4.
Gamora is agile, hits hard, and shows no mercy, making her a real powerhouse among the Guardians. She's not as tough as Groot and Drax, but her exceptional skill makes her harder to hit, and she can use blades and firearms with equal skill in any battle.
Thor. In Thor 1, he is no where near as powerful as he is in Ragnarok or Infinity War, but he is still strong enough to be considered a god by a physically superior race. He can control lightning, and Groot is a tree. He could instantly vaporize Groot, leaving him nothing to grow back from.
It's important to note that the rules around worthiness had been temporarily suspended to allow this to happen. As soon as the fight was over, Superman couldn't lift the hammer anymore. However, under normal circumstances, without any weird interference, Superman is worthy of Mjolnir.
Who would win in an MCU fight: Odin or Thanos? Without the Infinity Gauntlet, Thanos stands little chance against Prime Odin. Odin is stated to be able to shatter the Earth.
