I was reading an article about role-playing games, describing some of the "basic" nuances of famous fantasy instances - and describing "Warhammer Fantasy" as the most 80s of them, with punk-designed characters and the forces of Chaos being strongly reminiscent of radioactivity in pop culture. And it got me thinking again about various things.
When talking about nuclear bombs and radioactivity in fantasy, of course the first thing that comes to mind in recent landscape is The Lich from Adventure Time and everything around it. On a secondary degree it brings the actual main inspiration for Adventure Time, Bakshi's "Wizards!" one of the most famous movies of the "post-apocalyptic fantasy" genre. There's various takes on this genre but this specific chain (Adventure Time - Bakshi's Wizards) is one I actually like to tie to the Shannara books of Terry Brooks. As far as I know (outside of Jack Vance's Dying Earth, which does this VERY differently), Brooks was the first one to do an openly post-apocalyptic pop culture fantasy, deciding "What if Tolkien's Lord of the Rings was actually set in a distant future?" (I remember when I talked with @themousefromfantasyland about The Lord of the Rings they shared with me how post-apocalyptic The Fellowship of the Ring felt due to all the talks of fallen civilizations and haunted ruins).
And not only this, but Shannara partages something with both Bakshi's movie and Adventure Time: the concept that while a nuclear and/or technological apocalypse ended up creating a lot of mutants and artificial beings corresponding to fantasy tropes (orcs, dwarves, trolls and various monsters), it also mainly allowed for a return of magical beings that once dominated the world and are back after humanity is wiped out - fairies or elves. (Technically Jack Vance's works also sort-of fit in this, since it is implied that his Lyoness trilogy, set in an alternate Arthuriana, is the mythical past of the post-apocalyptic Dying Earth).
It is something quite different from other works that do have magic appearing with an apocalypse but it still wasn't there before. I don't know, this specific idea might have been floating around - it appeared as the master plan of the villain from "The Flight of Dragons" who precisely wants to create a nuclear holocaust as a way to prevent the magical realm from fading away and reclaim Earth for fantasy beings.
And you can also sort-of find it in "The Wheel of Time" series due to the whole "cycle" thing... Which leads me to my second point. Which was supposed to be my main point, but I digressed again. My point being that, as you all know, from late 80s to full 90s popped up a specific type of dark fantasy that would become what we know as the "grimdark" genre. With predecessors in games such as Warhammer (as I began this post with) or "The Black Company", but the most emblematic literary examples being mainly from the turn of the century, 90s/2000s. And the idea of a "fantasy verson of a nuclear bomb" is VERY prevalent among this generation. You know; the use of dragons in "A Song of Ice and Fire", and the Seed from "The First Law". And it is quite ironic that the predecessor, trope-wise, to this "fantasy nuclear-weapon" is not actually great grimdark predecessors, but rather... Pratchett's Discworld. I mean, his Sourcery was the first novel I know of that depicted explicitely wizard wars as being a literal nuclear war (I heard about something similar being alluded it the Heralds of Valdemar but I never checked this series)
[It is also quite funny how the nuclear bomb became such a central thing in fantasy when the work that developed modern fantasy was tied to the misconception that its main magical artefact was a nuclear bomb allegory, which everybody from readers to the author had to deny]
EDIT: Shit I forgot The Deplorable Word from Narnia. The ORIGINAL fantasy doomsday device. And seriously, for all its flaws (mainly born out of the Christian-propaganda-aspect), Narnia has such cool ideas. How crazy it is that you take the concept of "God created the word through his Verb" "God said a word, and the universe began", and then return it completely, into the idea that with just one word you can destroy all of the universe? Not even Le Guin in her Earthsea, despite being THE fantasy about magic words, names and verbs, does this... There's a "word of unbinding" but it is "just" a suicide-word.
EDIT 2: Damn I also forgot about about the explicit nuclear bomb comparisons in Zelazny's Amber books, about the magic of Chaos... Okay, don't hold anything I say above when it comes to chronology as interesting - see this post as just a compilation of works' name I think about as I go along.