While I have a very basic understanding of Thor, I've never read any of his comic books and, consequently, do not know the nature of his alter ego.
I know that Odin, wanting to teach Thor humility, stripped him of Mjolnir and his memories and "planted him" in the mind and body of Donald Blake. Was Donald Blake an avatar created by Odin (and is therefore just Thor in a cripple, mortal form), or was Donald Blake a real, pre-existing person who now shares his body with Thor?
If you circle back to Thor's start in '62 with the
Essentials books (as I've been doing the past ~6-7 months, since dumping his current ongoing) what comes through is that Thor and Donald Blake start out as the same person. Thor clearly works from Don's memories and shares his emotions, Don is able to appeal for help from Odin--definitely an avatar. The way I'm thinking about it at this stage is that Don as mortal disguise isn't a separate entity, he's a spell form wrapping and constraining Thor's real form, with tapping his walking stick/hammer being what flips the switch between the two forms. Or, if the walking stick has been tapped and converted into the hammer, Don's touching it will transform him back to Thor.
Now: on into the '70s--first time around, I didn't start reading MT regularly until the later '70s--this concept gets muddled. By '77-78 and on through until Simonson takes over, Don's cause as a character is pretty much lost. It's no longer clear that he isn't someone different to Thor, he's 99% irrelevant to the story, he basically goes through a variety of struggles to build a life and relationships of "his" own, and the results are just sad. Enough so to make me one of the people going "oh, thank you, thank you, YES!" when Simonson declares him null and void at the start of his run. The story at that point, is that Odin rules Thor's lessons in humility sufficiently learned, pulls "an old enchantment that had outlived its purpose" out of Mjolnir, over into BRB's Stormbringer, to allow for
his switching between his warrior and civilian alien forms...from then until the end of that run all that tapping Mjolnir does is switch Thor between his Asgardian regalia and whatever he's wearing for civvies as Sigurd Jarlson.
G'bye Don, until the beginning of JMS' run, when the hammer falls back to Earth again after Ragnarok, and in the
FF issue where that happens, we see a character with DB initials on his suitcase immediately buying a one-way bus ticket from New York to Oklahoma...where he heads straight for the crater where it's landed, says "I don't think so," and punches out the guys who object to his jumping the line for his turn to try lifting it, and *BANG* both he and the hammer disappear with an almighty flash of lightning.
So we start JMS'
Thor #1 with him showing up to call Thor back from the void of nonexistence... Note: rather a different Don, to the original. No longer the classic 98-lb-weakling "little guy" (loosely 5'4" - 5'6" back in the Silver Age, going by his height next to doors and other furniture) he's now a pleasantly average-looking fellow, and no longer lame. And, once the dust settles, he and Thor are back to something like their old arrangement. Sort of. Don's story is that "when the last god ceased to be" (Thor going to sleep in the void post-Ragnarok, at the end of
Thor: Disassembled) he popped back into reality as, apparently, a separate, mortal human (who will eventually be shot by a Doombot and lamed again, as well). He and Thor can now communicate as individuals (whichever is "out" sees the other in ghost-form), we get them consulting in the Void on one occasion when Thor's having a particularly WTF experience out in the real world...and there's no official explanation, so it's all a bit WTF as far as the reader's concerned. And then the last time we see Don, once Fraction takes over, is in a scene near the start of
World Eaters, when he's arguing with Thor over being let out to handle his business in Broxton, and Thor shuts him down with "Asgard first." I gather the next time we see him is at Thor's funeral after
Fear Itself.
However, I think I see a way this could work. Last time we see Thor as Donald is on Earth, standing on top of BRB's wrecked ship, completely freaking out because Odin has just swept BRB, with Mjolnir, off to Asgard, and he's in a sufficient state of shock not to realize, as Nick Fury points out, that his father
will recognize that isn't his kid, and come back for him. As Odin does, and Thor arrives in Asgard as Thor. My thought is that as Odin retrieves him, using his own magic to transform him on the way from Earth to Asgard, he strips away everything he identifies as Thor's mortal disguise. Physical appearance, clothes, most if not all of his medical knowledge and skills...
anything he doesn't instinctively identify as properly part of "his" son. This could include quite a lot of things being pushed off as part of "Donald Blake", which would in fact have
been part of Thor, growing through his human experience on Earth. Things like, just to grab a trivial reference from JMS' run, Don evidently has memories of watching the movie
The Fly, which Thor doesn't share, and of course Don is still besotted with Jane Foster, while Thor is caught up in a grand romance with Sif... Toss one bundle of "human" mortal disguise fragments, stuck together with residual energy from an Asgardian soul off into the void for a decade or two, where Don speaks of "walking a long time" (and my guess would be, growing "whole" again) and I'm thinking you could end up with exactly what we get.
Which is why it will not surprise me in the slightest, if sometime within the next year Fraction pulls some kind of "big reveal" exposing the two characters as damaged halves of a whole (hence Thor being everything everyone's complained about, since 2010) and either re-merges them, or...doesn't.
To be determined!
