Spoilers for Avengers: Infinity War follow below.
One of the most curious bits of casting for Avengers: Infinity War was the inclusion of Peter Dinklage. We knew the Avengers sequel would feature a ton of familiar Marvel Cinematic Universe characters, so the new additions were few and far between. Josh Brolin was playing Thanos, and eventually we learned the motion-capture performers filling out the roles of Thanos’ Black Order, but Dinklage’s role was a mystery until Infinity War was released.
Well it’s a mystery no more. When Thor (Chris Hemsworth), Rocket, and Groot visit the planet Nidavellir to forge a weapon to defeat Thanos, they discover the planet has been abandoned. The only person left is Eitri, which is Dinklage’s character. Eitri is a dwarf and master forger who created the Infinity Gauntlet for Thanos and is responsible for creating a number of other extremely powerful weapons. But when the Infinity Gauntlet was complete, Thanos killed everyone left on Nidavellir except Eitri.
Eitri is indeed a character from the Marvel Comics, who first appeared in Thor in 1983. He’s a Dwarf King who in the comics lived on Asgard and crafted Mjolnir for Thor.
Speculation ran rampant that Dinklage was playing a different character in Infinity War, Pip the Troll. While the filmmakers never confirmed this, Dinklage was spotted with what looked like orange hair when filming on Infinity War was underway, but alas, it appears that was just speculation that got out of hand—a cautionary tale about reading too much into things at times.
As for Thor’s new weapon Stormbreaker, well the name has a comics connection, but this appears to be an instance where the Infinity War filmmakers were simply homaging the comics rather than straight-up adapting them. In the comics, Stormbreaker is a weapon that was forged specifically for a character named Beta Ray Bill, who had just defeated Thor in a fight and had won Mjolnir. When he felt guilt over his victory, he handed Mjiolnir back to Thor and took possession of Stormbreaker, a different kind of hammer.
In Infinity War, Stormbreaker is more of an axe. But it is interesting to note that by crafting the handle and picking it up, Groot is proven “worthy” of handling a god’s weapon in the context of this MCU sequel.
So yeah, that’s where we’re at. Peter Dinklage’s big secret role in Infinity War was that of a dwarf craftsman, and Thor’s new weapon is a battle axe with a Groot handle. Comics connections are tenuous at best.