The odd thing about The Great Darkness Saga, long considered one of the most immortal Legion of Superheroes storylines, is how at odds with the style and flow of the book. It's a great story, it has a great epic sweep, insanely high stakes, and is pretty action-packed, and is tied in at an almost rabbinical level of Legion of Superheroes lore (of which there is a lot) but what comes out most plainly at me is how utterly odd it is, given that Legion of Superheroes is not a superhero book, really.
Oh, it has superheroes in it, but it's pretty much a romance comic in superhero drag. I was quite stunned in re-reading it decades later that really all of the action bits are pretty well dashed off before the issue's halfway over and then it's straight up soap-opera stuff: job stresses, relationship troubles, marriages, romantic misunderstandings, and, as with all romance comics, bundles of panels featuring women with their hand to their faces, a single tear spilling from their eyes.
I'm not saying this as though it's a bad thing--hell, the most popular books in the industry at this time had adopted the X-Men "keep the soap-opera going at all costs and make that the bits that people come back for month after month" storytelling model--but I can't think of a book that all but pushed the superhero stuff to the bare minimum of the equation like this one did.
My enormous Great Darkness Saga HC covers Legion of Superheroes #284-296 and the first Annual, and it's a very interesting slice of the book. The actual Great Darkness Saga only runs about 4 issues, and has been released with just the 4 issues, but in doing so, you really take the story out of context, and that's kind of a shame, as it's an interesting snapshot of a book at the peak of its popularity only scant moments before DC, motivated by greed, ends up tanking the book and catering to a mere handful of anoraks exploring ever more obscure continuity backwaters, most infamously making Element Lad gay because only gay dudes have man-fros. (I. . .guess? There's some real hair-related gay panic in DC comics) and then having to walk it back and taking a concept that collapsed so utterly in upon itself and having to take this thing out and sell it again to someone new while having no idea how to do that.
But at the time of this story, Legion is riding high, and from the bits and bobs of this story, apparently very busily trying to get out from under the very weird 70's days of the book (you know, the time that Cosmic Boy was wearing a bustier and shit) and making it a bit more of its time (inasmuch as a book written in the early 80's about the 30th century can really be of its time) and point itself in a new direction while still keeping the critical bits of the Legion lore in play.
Which is why Great Darkness is such a weird story. It uses a lot of current-day DC Universe backstory (which Legion almost never did apart from you know, Superboy) which it can;t even be fussed to explain (there's a hilarious editor's note that says, essentially "You know what? We can't explain the New Gods stuff either") and . . .man, there's something about the notion that the book is not willing to explain all that much (and if they're not willing to tell you that much, you can for damn sure imagine you're on your own trying to figure out who the hell the Heroes of Lallor are supposed to be) which is a . . .well, it's an interesting choice, as the writer of the piece, Paul Levitz, is basically throwing a story that turns on every bit of Legion Lore and characters accrued to this point and the whole Fourth World stuff at you, not really pausing to explain any of it and yet . . .
. . .and yet it kind of works on this base level in that you're presented with something built up as suitably apocalyptic and if you go in knowing none of it, it still plays as "epic," because it's treated as an epic thing, and that comes across on a base level, even if the rest is not really known. Crisis, actually works on that level for the uninitiated, in fact; the less you know about DC universe lore, the better it plays, but that's another write-up.
It's interesting that the story works so well, with everything against it (not least because this kinda stuff doesn't really happen in soap operas, does it?) and given it's rather anomalous circumstances, it's no wonder it stands out so. Even if it didn't work, it would probably be an interesting failure (as the sequel story was, sadly enough) but that it does with so much against it, it's kind of even more intriguing.