Avengers: Endgame contained a middle act where the heroes time travel, but the location visited by Thor and Rocket was almost drastically different from the ones they visited in the movie.
Avengers lost, and they took out their anger on Thanos by killing him in 2018 which was a huge surprise, few days after the mad titan snapped away half of the world’s population. In his belief to restore balance to the universe Thanos dedicated the latter part of his life searching and collecting the Infinity Stone which holds all of the realities together.
With the loss at the hands of Thanos and five years passing, there was no hope for the heroes to bring back what they lost. But all of it changed when thought to be snapped away Ant-Man comes back from the quantum realm and gives all of them hope about a time heist. This results in the heroes getting back together and making a time machine to travel back in time and collect all the stones and snap the population back to life. In the brainstorming session, the heroes decide to go to three different timelines in four teams to retrieve all the stones. But in the Blu-ray version of the movie, there was a little easter egg, something which showed the thinking process of the writers and something which would’ve changed the timeline where Thor and 'Rocket' went.
Exactly at the two hour one minute mark of the home media version of the movie, we can see the time travel control panel which shows the date of the Battle of New York and also there is a little easter egg of November 2009 but we are here for the third date between the two, 2988 BC.
According to the control panel, Thor and Rocket would’ve gone thousands of years in the past to retrieve the Aether. And yes, 2988 is a BC, in the top right corner of each date you can see a toggle where the AD switched up, and in the middle date, the toggle is switched downwards. So, what exactly happened in 2988 BC, and why were they thinking of going so deep into the past?
Source: Marvel/Disney Blu-ray screenshot
The answer is hidden in Thor: Dark World (never imagined Dark World would’ve mattered so much in the MCU) during a short prologue in Thor: Dark World we see the fight between Asgard’s army and the 'Dark Elves' during the battle of Svartalfheim. During the convergence of the nine realms, Malekith the leader of the Dark Elves controlled the Aether and was about to use his power given by the reality stone but, 'Bor,' then king of Asgard and Thor’s grandfather used the power of the Bifrost to take away the Aether and hold off Malekith.
According to the control panel, Thor was planning to take Rocket in the middle of the battle and one of the most important moments in the MCU history. Bor was a great king and seeing him in battle from a different perspective would’ve been nice, and the whole battle sequence would’ve been pretty awesome to see again after only touching it for a brief moment.
Watch: King Bor vs Dark Elves battle scene in 2988 BC during the prologue of Thor: Dark World
Would we change the event of Endgame so we can see the epic battle? With a heavy heart we need to say no, the whole thing about traveling to Asgard to get the Aether in the first place wasn’t really about getting the Infinity Stone, it was about Thor finding closure after the death of his mother. Thor doesn’t even get involved in stealing the stone, but he does meet his mother who knows Thor is not the one she knows. He words are inspiring to Thor, telling him to live the life he is meant to live and not what people expect him to live.
The closure and the advice Thor finds with his mother to be true to himself is something irreplaceable, and we don’t think Bor would’ve been of the same impact to his grandson. Another little aspect of Thor traveling to Asgard was he was able to call Mjolnir to him, which reinforced his mother’s idea and made him certain he is still worthy of being Thor.
Watch: Thor calls for Mjolnir in Avengers: Endgame
By the way, it would’ve been easier to go to 2988 BC to retrieve the stone because the stone was still in sludge form and to get the stone from Thor’s grandfather would be easier than trying to stick a needle in Jane Foster (who is returning as Thor in Phase 4). Also, Captain America’s work of restoring all the stones to their respective timeline would be much easier if he traveled to Asgard in 2988 and put it inside a vault than trying to inject it back into Jane.
Whatever the case, the stones allowed Thor to live one meaningful moment with his mother for the first time in the MCU. The death of Thor’s mother at the hands of the Dark Elves just came across as cheap motivation, but in retrospect, her death was the catalyst for the changes in Thor’s life. With his story coming back full circle and him even knowing what was about to happen and still his mother choosing her fate was an endearing moment, something which provided a level of sorrow and grief but also let Thor know he was not at fault.
Source: Marvel/Disney Blu-ray Screenshot
A boy needs his mother, and the decision to send Thor to 2013 Asgard was something which brought closure but also allowed him to say goodbye to his mother, which he was never able to in Thor: Dark World. We don’t think Thor would’ve been better off if he went and talked to his grandfather, someone who he never met, there wouldn’t be the same amount of impact. But if there are any cut scenes or storyboards or even script material, the people at Marvel must do the right thing and release then all.