This was one of the first monumental stories in DC's post-Crisis on Infinite Earths history. Following the epic mini-series only a few months afterward it had a lasting shadow on the first half decade of the new DC Universe. As a result of the Crisis and the streamlining of DC's convoluted history and parallel Earths into one unified universe/timeline, the JSA as it was known, wasn't really welcome in the DCU anymore, and the man who'd shepherded the wartime heroes into the Bronze Age was, fittingly, the one to send them off.
Roy Thomas was kind of the Geoff Johns of his day. He was the writer that was simultaneously unwilling to let go of his childhood toys, his favourite iteration of DC's heroes, but also perfectly willing to move them forward. He not only toyed with them in their heyday in All-Star Squadron, and introduced a wartime Teen Titans in the Young All-Stars, but also formed a team from their offspring with Infinity Inc. As the 70's started delving more heavily in continuity and how past adventures fit with modern stories being told, Thomas was instrumental in smoothing out a lot of the Golden Age backstory and having it jibe with stories of the late-70's and '80's.
Much like how Flashpoint and the New 52 undid years of world building, the Crisis undid most of Thomas' devoted legacy building. Like how Batman and Green Lantern were able to continue on relatively unscathed in the New 52, many titles carried on post-Crisis, creating a bit of headache work for the editors and writers. Infinity Inc. was able to keep going for another two years, with Thomas working to help make sense of how the legacy of the Golden Age heroes had changed while most other writers tried to avoid the subject in the first few years.
The Last Days of the JSA Special is a bit of a headache of a book as Thomas tries to explain the events of the Crisis, how the Golden Age versions of Superman, Batman, Wonder Woman and their supporting casts (essentially the Earth 2 versions of these heroes) were removed from general consciousness, and how he could remove all of the remaining legacy heroes from common use (except those like Dr. Fate needed elsewhere) so that modern heroes could take their inspiration from them, but not interact with them.
Hawkman notes that they are but the few who remember multidimensional life before the Crisis and that this is no longer quite the world they knew. He also explains how he, and his teammates are no longer needed in this new, overpopulated-hero world, and that retirement is the best option before them. But the Spectre, a beaten mess after his clash with the Anti-Monitor, warns that there is problems with the merging timelines (or something) and that disaster will befall all of Earth if the Justice Society does not intervene.
The disaster, well, it's caused by Hitler, who in his final days, turns to the dark arts, wielding the Spear of Destiny, summoning Ragnarok and Earth's ultimate doom. Dr. Fate places the Justice Society in place of the Norse Gods (well some of them) as they battle the ensuing hordes of monsters, demons, giants and undead. The battle is won, but it's a neverending victory as no death is finite and everyone must rise to fight the battle again. But each time the victory, though always costly, is won, thus defeating Hitler's ploy but leaving our heroes stuck in limbo perpetually...
...until 1992 when the new Justice Society of America series is launched after the events of Armageddon: Inferno. It seemed so much longer.
Thomas' narration here is brilliant, subtle and frequently obtuse in a poetic way, particularly surrounding the Hitler sequences in WWII. It's unfortunate then that his dialogue is so painfully hyper-expository, the type where the characters shout out what's happening on the page. It's a style of writing that carried from the 30s clear through until the mid-80's which always annoyed me. There's an artist there for a reason, and it just seemed like writers never trusted the art to tell the story. David Ross's muddy linework feels like a Sean Phillips precursor, frequently stiff figurework and an uncomfortableness with the stereotypical spandex look and the fantasy aspects are evident (he would excel at crime comics to be sure). His tone, however is perfect for a "Last Days" book, the ominous, bleak sensation ever present.
It's a whopping 68-page, ad-free, stapled book that even makes use of its inside front and back covers for Thomas to detail the origin and intent of the project. Overall it's not essential but definitely intriguing time capsule, a decidedly epic read, but kind of meaningless unless you know the history...