There’s no shortage of powerful weapons in the MCU. In the old days, there was the Iron Man armor and Captain America’s shield. The arrival of Thor and his enchanted hammer Mjolnir then opened the franchise up to cosmic weaponry while Avengers: Infinity War revealed the full might of the Infinity Gauntlet and the Stormbreaker ax, both of which were created on the planet Nidavellir at the hands of Eitri (Peter Dinklage).
Avengers: Endgame revealed yet another immensely powerful weapon though, Thanos’ sword that he used to break Captain America’s shield and counter both Mjolnir and Stormbreaker at the same time. With such formidable power wielded by the sword, fans have naturally been curious to find out just where such a piece of weaponry could have come from.
Thankfully, the audio commentary track that accompanies the digital release of Avengers: Endgame provides a clue in the form of the following exchange between the film’s writer Christopher Markus and director Joe Russo:
Markus: While vibranium is the strongest substance on Earth, whatever Thanos’ straight razor there is made out of is stronger.
Joe Russo: Well Thanos clearly knew Eitri.
So, it seems that Eitri of Nidavellir was responsible for adding yet another powerful weapon to the MCU roster. Since Thor’s hammer and Stormbreaker were known throughout the universe for their immense power, it makes sense that the only weapon that could counter their might was also created from the same forge that they were. Looks like the Avengers need to keep a close eye on Eitri, who’s apparently Tony Stark on a cosmic scale, so that he doesn’t make any more world-ending weapons and hand them over to any future megalomaniacs bent on universal destruction.
Of course, Thanos’ sword was destroyed in Avengers: Endgame and its remains are still presumably on Earth. This has led some fans to speculate that its metal will be used to create the claws and exoskeleton of Wolverine when he finally shows up in the MCU. While that would be a neat way to tie him into the larger picture in-universe, it would make Marvel’s Logan, a character that fans can only fantasize about for the moment, a freshly created superhero instead of the 90-years-old (and counting) superhuman we’re familiar with from the comics and movies. In other words, as cool as it sounds on paper, it may not be the best route to head down.
