Creating New Weapons
Since Eitri is expected to return in Avengers 4, we have to wonder why. Considering the powerful weapons he's already created in the past, it may be that Eitri is visited again to give the remaining heroes weapons of their own. There was recently a leaked piece of concept art for Avengers 4 that unveiled a brand new axe that will reportedly be in the movie. Early speculation has turned to Brie Larson's Captain Marvel being the owner of this axe. However, there's no signs that she'll have this in Captain Marvel, so it may instead be given to her in Avengers: Infinity War. It will need to be created first and Eitri is the best bet to do so, and there's some precedence in the comics for this to happen.
During Marvel Comics' 2011 crossover event Fear Itself, Carol Danvers (then going as Ms. Marvel) received a special axe not too different than the one in the leaked image. She is so far from the only hero to receive a special weapon to help defeat Red Skull's daughter, Sin, and Odin's brother, Cul Borson. As part of this storyline, Iron Man journeys to Asgard to plead with Odin to let him create powerful weapons for Earth's Mightiest Heroes. Odin grants this request and Stark creates this axe for Captain Marvel, but also special web shooters for Spider-Man, arrows for Hawkeye, an Uru sourced suit for himself, and much more. Something similar to this may be happening in Avengers 4.
When Star-Lord asks Thor in Infinity War why everyone shouldn't receive weapons capable of killing Thanos, Thor responds by saying, "You simply lack the strength to wield them. Your bodies would crumble as your minds collapsed into madness." Marvel's been hyping up Captain Marvel's power with her being described as having an unprecedented power level. With the possibility that she can move planets, she could surely wield a weapon capable of killing Thanos like Thor does. The question then turns to the rest of the heroes. Will Eitri just create the axe for Captain Marvel? Or, will we get to see Iron Man get an Asgardian inspired suit, Captain America get a more powerful shield, Hawkeye get special arrows, Black Widow get new batons or swords, Rocket receives specialty bullets or a gun, and maybe even have Hulk receive a weapon or two of his own? All of this could be in play if Eitri is called upon to help the heroes.
On the other hand, we can't discount the possibility that Eitri will also be responsible for creating new weapons for Thanos. More concept art for Avengers 4 revealed a great look at Thanos' new sword, and it's more than likely Eitri plays a hand in that. There's no clear reason why Eitri would still listen to Thanos after he proved he couldn't trust his word before, but the sword is just as possible to be a Eitri creation as anything else. As if these options weren't enough, there's something else both sides could look to Eitri for help creating.
Another Infinity Gauntlet
Eitri still has the mold for the Infinity Gauntlet and there's at least an explanation on each side of this war that would explain why they'd go to Eitri and ask him to make another Gauntlet. It would, of course, be up to Eitri to oblige either request, but he could be asked to make another and who it could be created for would have major repercussions.
Staring with Thanos, we already know why he would visit Eitri. The Russo brothers previously confirmed that the snap permanently damaged Thanos and the Infinity Gauntlet. This could make it difficult, if not impossible, for Thanos to use the Infinity Stones individually or collectively in Avengers 4 with the current state of his Gauntlet. He could visit Eitri again to get a brand new Gauntlet. Promising to restore Eitri's hands could be enough to convince him, but he's also been betrayed by Thanos before, so it may just be the result of Thanos forcing him to do so.
The other option is that the Avengers visit Eitri and, whether he gives them new individual weapons or not, they ask him to build them their own Infinity Gauntlet. There's plenty of theories that Avengers 4 will involve time travel and that the Avengers will be hopping around the timeline grabbing the Infinity Stones. If that is their plan to undo the snap, they'll need a Gauntlet of their own that is powerful enough to hold the Stones, and Eitri is the only one who can make it.
However Eitri gets involved, he will be appearing in Avengers 4. With several potential items capable of coming from his forge, which ones he makes and who they are for could decide who is victorious in Avengers 4.
- Captain Marvel (2019) release date: Mar 08, 2019
- The Avengers 4 / Avengers: Endgame (2019) release date: Apr 26, 2019
- Spider-Man: Far From Home (2019) release date: Jul 02, 2019