John Byrne's 1980s tenure on the SUPERMAN titles has almost nothing to recommend it in terms of symbolic discourse. In every way, Byrne seemed dedicated to reducing the florid creativity of the Silver Age down to his drably functional revisions. Still, his revision of the Weisinger version of Krypton was not entirely of his own invention, but was borrowed from the 1978 Richard Donner film, wherein the Man of Steel's homeworld was re-imagined as a glacial, over-technologized place.
Given Byrne's enthusiastic endorsement of the Donner Krypton in his 1980 COMICS JOURNAL interview, one might have thought he'd never want to write any stories about such an unappealing environment.
Yet the 1987 WORLD OF KRYPTON, written by Byrne and (principally) penciled by Mike Mignola, is the only time Byrne contributed anything interesting to the Superman mythos.
The story begins a thousand years before the birth of Jor-El, with Van-L, father of Jor-El. In those days, Kryptonians enjoyed near-immortality, hardly ever bothering to sire children, thanks to their advanced techniques in cloning. The opening sequence of issue #1 makes clear that most Kryptonians live a privileged life.
Clone technology makes it possible for Van-L's potential girlfriend Vara to be instantly repaired when she loses an arm in a crash. However, the ethical debate over the immorality of cloning is growing, because the clones are kept in stasis and never allowed to take on individual identities. (The "anti-clonists" use the slogan "minds for the mindless" a couple of times.) Eventually Vara-- whose name references that of Superman's mother "Lara," though she's presumably no relation-- becomes a radical "anti-clonist," and accuses her fellow citizens of being virtual "cannibals." However, what really stokes the cultural conflict-- and even leads to a series of destructive wars-- is the abuse of a clone by Nyra, the mother of one of Van-L's contemporaries, one Kan-Z.
What kind of abuse? Well, I referenced this particular taboo in my analysis of Jerry Siegel's 1960 "Superman's Return to Krypton"-- but where the taboo in that story is purely symbolic within the boundaries of the narrative, Byrne's KRYPTON makes the taboo of incest more literal. Nyra, because she does not believe any woman is good enough for her son Kan-Z, abducts one of her own clones from its facility,. Somehow she contrives to grow the clone to maturity, educate her, and give her a separate identity, all for the purpose of marrying her son to a version of herself. Kan-Z's reaction is to kill his mother and her clone, and to attempt his own death. Later Kan-Z too becomes an ally of the "clones rights" terrorists, whose most radical group is called "Black Zero," after this earlier Superman villain.
Apparently in Byrne's world incest is worse than cannibalism, for the scandal of Nyra's deed sparks a thousand-year-war, as well as the ultimate destruction of the planet by Black Zero. As if to disavow the sybaritic lifestyle of earlier Kryptonians, the post-war Kryptonians become extreme isolationists. They no longer need clones to extend their lifetimes, having invented other anti-aging techniques, but they've become the inhumanly glacial humanoids seen in Donner's film and Byrne's rewrites.
Mignola's art is consistently gorgeous, but Byrne's ability to invest his characters with dramatic heft is seriously lacking. However, I will give props to the schematic sociological myth he devises for Krypton: first too sensuous, then too abstemious. This stratagem succeeds in characterizing the homeworld of DC:s pre-eminent hero in terms of unpleasant extremes, as against the "divine middle" embodied by the Planet Earth.
Given Byrne's tendency to rewrite earlier stories. it's not hard for me to believe that he caught onto the way Jerry Siegel concealed the quasi-incestuous theme of his story by giving Superman's Kryptonian lover the name "Lyla Lerrol," a shuffling of the name "Lara," Byrne thus creates both a bad mother and a not-so-good girlfriend, Nyra and Vara, before introducing the "good mother" who will make possible the birth of a "savior" of sorts. Byrne doesn't devote nearly as much attention to the two main male characters, dramatically or symbolically. Van-L's name doesn't seem to hold any strong associations, though an old SUPERBOY story does state that one of Superboy's ancestors is named "Val-El." As for "Kan-Z," I can't help but note that his name resembles that of the American heartland where the infant Kal-El ends up; i.e., "Kansas." But the latter confluence may not have been consciously intended.