Of all of the Avengers, it's possible no character has gone through quite as many changes as Thor. He's found and lost loves. He's lost and regained eyeballs. He's learned things about the father he idolized he never would have expected. Needless to say, in Avengers: Endgame a film that we knew was going to change the status quo of the Marvel Cinematic Universe, Thor continues to change and Chris Hemsworth says he worked closely with directors Joe and Anthony Russo to figure out just what they could do to change things up in the new film. According to Hemsworth...
They were on board and we sat for many hours and days and discussed kind of how far we could push it and what we could do different. It was great that was welcomed, you know, that kind of [conversation].
Of course, since Hemsworth's comments with USA Today came before the premiere, the actor wasn't talking about exactly what sort of changes took place (and we won't either until further down).
The first Thor movie was directed by Kenneth Branagh, and Branagh's Shakespearean background comes through quite clearly. Thar, and most of the rest of the Asgardians, speak formally and carry themselves with a strong feeling of self-importance. However, as Thor continues to interact with humanity throughout The Avengers movies and the Thor sequel, he becomes a bit more, well, relaxed. This hits an extreme with Thor: Ragnarok, where Thor has evolved into a very different character. He uses his wit as well as his hammer as a weapon.
While other MCU characters have certainly had interesting arcs, nobody's has been quite like Thor's. He started as a egotistical brat who assumed he would be king, to becoming a reluctant leader who made one of the most difficult choices imaginable when he sacrificed his home in order to save his people.
This seems to largely be because Hemsworth himself wanted to see these changes. He's spoken about being somewhat tired of Thor before Ragnarok, so he was probably quite excited about what else he could do with the character in the new movie to continue to keep things interesting for him.
From here, we're getting into Avengers: Endgame SPOILERS*_,*_ so turn back if you haven't yet seen the movie. Here's a picture of Thor flexing for his earthling roommate to keep you entertained.
When Avengers: Endgame makes its five-year time jump into the future, we see that Thor is having a particularly hard time dealing with the loss. As the man who came closest to stopping it all, Thor blames himself, and he's really let himself go as a result. Tony Stark at one point calls him "Lebowski" and it's almost too perfect a nickname.
Thor has something of a new attitude to go with his new physique as well. His confidence is gone and he's even more laid back than we've seen him before. He's about as far from Branagh's Thor as it's possible to be. Chris Hemsworth and the Russos have certainly pushed the character quite far.
What this means for the future of the character, we don't know. While some Avengers stories have seemingly come to an end, his certainly looks to have more left to go.
Avengers: Endgame is in theaters now.