Superhuman Durability: Groot's hide is composed of wood dense enough and durable enough to make him immune to most conventional weapons, including gunfire and fire which would consume most woods.
That is unless you're going up against Groot and his super durable bark, which is composed of a bioreactive material native only to his homeworld known as “sentient wood.” This dense wooden hide is tough enough to withstand most conventional weaponry (or annoying insect infestations) making him truly a Flora Colossus.
Groot probably grew the densest, tightly gripping handle (much stronger than any woodwork on Earth) around Stormbreaker's metal parts before severing it.
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.
Who is Marvel's Groot? You're Barking Up the WRONG Tree!
Why could Thanos hold Stormbreaker?
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.
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.
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.
Thanos can't lift Mjolnir… usually. The parameters for “worthiness” in Mjolnir's enchantment are rather vaguely defined, people tend to debate a lot about what exactly constitutes someone as “worthy”.
This may be related to his cellular regeneration and his control over plants. 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.
Hulk & Groot's Original Battle Confirmed They're Equals
The fight is remarkably close - Hulk's blows fail to knock Groot down (since he's rooted to the ground), and the Flora Colossus is able to both send Hulk flying with a punch and restrain him with vines and branches.
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.
At full height, he can reach 23 feet tall and weigh 8,000 pounds. Thanks to his super strength and knowledge of quasi-dimensional engineering, this Guardian is a formidable adversary for any Super Villain threatening the universe.
While being resistant to flames might not seem all that special, for a giant wooden tree, this power is nothing short of miraculous. Groot's alien wood composite provides immunity to most fire. The first glimpse of this remarkable talent came during his debut in Tales to Astonish #13.
Even though Groot can consistently lift 100 tons, his strength is essentially limitless. Since he can increase his size and effortlessly regenerate parts of his body, Groot can multiply his strength with ease. Even without relying on changing his size, Groot's base form outclasses some of Marvel's most powerful heroes.
That said, his son spent his entire life with the Guardians and learned much of his survival skills from them. As a result, he likely got bigger to emulate Drax's strength.
Without the Infinity Gauntlet, Thanos stands little chance against Prime Odin. Odin is stated to be able to shatter the Earth. And he turned Frigga into stars. He has devastated while worlds, laid waste to kingdoms and destroyed demons and monsters.
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.
But as it turns out, it was not just Thor's strength. After all, no weapon in existence should be able to stop the combined power of the Infinity Stones, no matter how powerful the wielder is. Turns out, Thanos was taken unawares. He had just incapacitated all the heroes who tried to stop him.
He was able to lift Stormbreaker because Stormbreaker is purely about strength. In Infinity War, when Thor was asked by the Guardians of the Galaxy, Peter Quill: Don't you think that we should all have a weapon like that?
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.
In Infinity War, Thor explains that learning Groot was a mandatory elective he had taken. It is similar to how many American schools require students to take a foreign language such as Spanish, German, French, Chinese, 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).
Stormbreaker survived a full blast from the IG utilizing all of its stones. Actually, not only did it survive, it overpowered it. Unless you think Hela's grip and innate powers is more destructive than all those stones combined then the answer is no, she can't destroy Stormbreaker.
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.
