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 isn't worthy, he doesn't need to be worthy to pick up two unfinished parts of the weapon and join them. How durable is the handle Groot made for Thor's new battle axe “Stormbreaker”? No matter how strong Groot is, but cannot forget he strongly relies on his regenerative factor and the handle is made of wood.
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.
While no one besides Thor has been able to truly wield the awesome might of Stormbreaker, Groot was the very first being to hold this weapon when one of his arms became the handle for the mighty axe.
Here's How Groot Could Lift Thor's Hammer In Infinity War
How did Groot hold Stormbreaker?
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.
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.
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.
Mjolnir has the enchantment where only those who are worthy can wield it, such as Thor or Captain America. Hulk on the other hand, … while Stormbreaker can be wielded by anyone who has the strength to do so (though it can be summoned by those worthy of Mjolnir like Cap did). Case in point, Thanos.
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.
As Thor described in Infinity War, Stormbreaker was a “Thanos-killing” weapon. Like Mjolnir, Stormbreaker is one of the most powerful weapons in the universe, and both Uru hammers nearly deal killing blows to Thanos in both Infinity War and Avengers: Endgame.
Not Mjolnir. He is likely unworthy, so he would not have been able to lift up Mjolnir by himself. However, he did grab Stormbreaker, which DOES NOT have a worthiness enchantment.
Superhuman Strength: Groot's tree like form provides him great strength and enables him to lift more than 100 tons. His strength allows him to overpower Armadillo.
Although Stormbreaker and Mjolnir have very similar properties and powers, Stormbreaker is the most powerful weapon wielded by Thor so far. The obvious reasons are that Stormbreaker is the physically larger weapon out of the two, and not to mention that it is an axe, which could well be more dangerous than a hammer.
Groot's abilities are all-natural and stem from the dendronic wood that makes up his entire body. The extraterrestrial bark he was born with makes him invulnerable to most projectiles and even fire. He can control all plant life via psychokinesis, absorbing it into his body and making himself stronger.
Thor hypes up the weapon which eventually became Stormbreaker in Infinity War as the "Thanos-killing kind" of weapon. However, there is a clear weakness between Stormbreaker and Mjolnir.
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).
The movie doesn't explain Thor's motivations for giving up Stormbreaker, but it makes sense that Chris Hemsworth simply wanted Love to have a powerful weapon to aid her in battle. It's unlikely that he could give her Mjolnir, considering that so few people in the MCU have been deemed worthy of its power.
The most likely reason is when Groot's arm was separated from him, it became a part of the full weapon and was enchanted to be virtually indestructible. Stormbreaker is a weapon of Nidavellir, which are magical, so it's entirely possible.
Hulk triumphs, but it's more thanks to his tactics than superior strength, first uprooting Groot by attacking the ground, then using a boulder to fend off his powers and smash him to pieces.
He participates in the conflicts against Ego and then Thanos, falling victim to the Blip before being resurrected five years later by the Avengers and participating in the final battle against Thanos before departing for space with the Guardians.
Gamora is more skilled and she's just the better fighter. That's her main advantage given that she's an assassin, She probably would try to outmatch Groot in skill as they have encountered before.
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.
