With all the Marvel excitement right now centring on Captain America: Civil War and finishing up on Doctor Strange towards the end of the year, it's easy to forget that we're currently on the road to what is likely to be the final piece in the Thor trilogy, Thor: Ragnarok.
Now there's been plenty of rumors swirling recently that a big name Avenger is set to bite it soon in the Marvel Cinematic Universe, and Thor's name has been tossed around in this debate more than a few times. Cause, you'know, Ragnarok and all that.
Though it's a little unlikely that Thor will actually die in his next film (not least because Hemsworth is still contracted for three films including the Infinity War two parter) it wouldn't exactly be a break in continuity if he did. Comic book characters have a habit of being killed off but not staying permanently dead, and Thor is no exception.
There's been a lot of speculation as to which storyline Thor 3: Ragnarok is going to follow; but the most likely of the bunch involves the most recent occurrence of Ragnarok within the Marvel comics universe.
At the end of this particular Ragnarok cycle Thor enters into a limbo-like stage of hibernation, during which time he is believed dead by his fellow Avengers. Shortly after this Mjölnir is found on Earth and put under US Army protection, pretty similar to what happened in Thor when S.H.I.E.L.D. found the hammer in the desert.
Doctor Doom later tries to take possession of the hammer but fails, and Mjölnir makes its way into the hands of a man carrying a bag marked "D.B" - Donald Blake, Thor's earthbound alter-ego. Blake eventually succeeds in combining the two personas again, bringing Thor back to life.
So, though it's unlikely that Thor will die (permanently anyway), there's every possibility that in between Ragnarok and Infinity War everyone's favourite Thunder God could go missing in action, especially if Asgard does end up being destroyed. Thor's gone waltzing off leaving Mjölnir behind several times in the comics, so it wouldn't be unusual to see this adapted into the MCU.
What Could Happen To Mjölnir After 'Thor 3'?
Thus far in the MCU the only other hero we've seen lift the hammer was Vision, in The Avengers: Age Of Ultron.
This scene is amusing as it recalls earlier in the film where, at a party, all the Avengers try to lift the hammer and fail (with the exception of Steve Rogers (Captain America) who manages to shift it a little, much to Thor's displeasure).
However there's been a number of other characters in the Marvel Universe who have wielded Mjölnir at some point or another (although most of them have not yet made an appearance in the MCU).
Beta Ray Bill
Beta Ray Bill is one of those characters that seems unlikely to be adapted in the MCU, but then everyone thought that about the Guardians of the Galaxy and look how that turned out.
Beta Ray Bill is a horse-faced alien who has been around in the comics since the 80's. Though he appears monstrous Bill has proven himself to be a great hero, and so is the first non-Norse Marvel character to be deemed worthy of wielding Mjölnir.
Of course Thor isn't too happy about this to begin with, so after a while Beta Ray Bill is given a hammer of his own named Stormbreaker and they both get along much better after that, becoming close allies.
Beta Ray Rill also appears in the most recent Ragnarok storyline (mentioned above) in which he is saved by Thor, so you never know...
Thunderstrike / Eric Masterson
Another character who has served as Thor is Thunderstrike / Eric Masterson, and he's also been kicking around since the 80's. Initially human, Eric Masterson was an architect rescued by Thor and given the Thunder God's powers in order to save his life after being mortally wounded by the super-villain Mongoose (cause getting killed by someone called Mongoose is just embarrassing).
Masterson and Thor get separated and merged a few times; one such instance occuring when Thor is banished. He gives Masterson possession of Mjölnir, and Thunderstrike joins the Avengers to serve in Thor's place. As part of the Avengers he's present during the Infinity Gauntlet story arc, which ties the character into the MCU.
Thor eventually returns to reclaims Mjölnir and - as in the case of Beta Ray Bill - Thunderstrike ends up getting his own mace from Odin in order to reduce competition for Mjölnir. There can be only one...
Back when it was announced that the new Marvel Comics Thor was a female there was some confusion in the non-comic book reading community. Had Thor finally conceded to wearing his mother's drapes? Did Donald Blake get a sex change?
However, as is common knowledge by now, the 'female Thor' is not literally a female version of the Asgardian, but rather Jane Foster wielding the legendary hammer and in doing so gaining the powers of Thor.
Jane Foster lifts Mjölnir after the Original Sin story arc in which Nick Fury tells Thor a secret that renders him unworthy to lift the hammer (like in Thor when he finds Mjölnir in the desert and is unable to lift it due to the actions that caused his banishment from Asgard).
After witnessing her wielding Mjölnir Thor concedes his title to Jane, though he is unaware of her true identity due to the fact that her mortal form is weakened; currently she's undergoing chemotherapy for breast cancer.
Currently Jane is still wielding the hammer as the Thunder God(dess) in Marvel comics' Thor, and serving as a member of the Avengers.