Though this sounds like the stuff of comic-book epics, "Secret Origin of the Guardians" is wrapped up in one issue, and for good measure throws in the first meeting of the Golden and Silver Age Lanterns, outside the pages of their initial Justice League encounter. A bare summation of the plot also sounds like par-for-the-course with DC story-lines:
"An evil alien, imprisoned as an energy-form inside a meteor for his crimes, enters Earth's atmosphere and suborns one of Earth's heroes to carry out new crimes. The alien even makes one Earth-hero fight another one until they join forces and overcome the evildoer." True, in "Origin" the two heroes come from different versions of the Earth, but the parallel applies nonetheless. The cover seen above is also extremely familiar, as even by 1965 DC Comics had published innumerable covers in which a featured hero found himself about to be marginalized or replaced by a rival. However, the quality of the mythopoeic is much like the saying about the Devil: "it's in the details."
The first four pages of the story proper deal with Alan Scott, the Green Lantern of Earth-Two, coming into contact with the meteor. The object's radiation temporarily nullifies the weakness of Scott's power-ring-- a vulnerability to wood. Immediately thereafter, rather than testing the meteor's properties, Scott decides to go to Earth-One and see what the Hal Jordan Green Lantern thinks about it, in case the meteor might be able to banish the weakness of Jordan's Guardian-given ring.
As soon as the two Lanterns meet, Jordan reminds Scott (in a totally nice way) that Scott could have verbally asked his ring to analyze the meteor, since the ring can do almost anything, including communicating info like a miniature computer. The ring then informs the crusaders that within the meteor was the imprisoned villain Krona, who hails from a time from the race of Oa, the race that later involved into the Guardians-- thus allowing author Broome a quick way to communicate said history.
"Ten billion years" ago, the Oans were a race of blue-skinned super-scientists, who were immortal and did not need food or rest. They lived an untroubled, pre-lapsarian existence, not yet evolved into a coterie of aged blue dwarves (they even have women and childbirth at this point, which would lead to a complicated set of retcons in later GREEN LANTERN stories). But one among them, Krona, aspires to "probe the beginning of all things," despite a legend that claims that the universe will end if the Guardians learn their origins.
As the excerpt shows, Krona does get a peek at the cosmic beginnings, and sees what one must presume to be the Hand of God Himself, shaping the cosmos. However, this peek isn't enough to wipe out the whole universe; it unleashes "cosmic lightnings" that zap Krona but don't kill him. The non-immortals of the cosmos pay the real price, for "evil was loosed on the universe," which presumably had existed in some sort of Edenic state up to that point. Because the Oans feel guilty over Krona's actions, they imprison in the aforesaid meteor and hurl him into outer space-- after which they decide to organize the Green Lanterns in order to quell the evil in the universe.
Scott's ring also informs him that the only reason that it gained immunity to wood was because Krona wanted Scott to have a reason to cross into the Earth-One universe, because only in that universe can Krona continue his forbidden researches once more. Once the ring finishes its story, one of Jordan's Guardian-mentors shows up on Earth-One, informing the two heroes that Krona's activities will soon cause an outbreak of disasters, even before he finds out the Big Secret. The Lanterns spend a few pages fighting natural cataclysms, and are then summoned to the base the Guardians have made on Earth-- where the Guardians suddenly justify the cover and announce Alan Scott to be Hal Jordan's replacement.
The solution of the cover-conundrum is weak at best: for some reason Krona decided to steal a march on the heroes before they came after him, by possessing the body of Scott and mentally manipulating the Guardians. This questionable strategy leads to a battle of the Lanterns, which Krona easily wins. Krona then transports the paralyzed Guardians to his hidden lair, boasting that he will make them watch their own "secret origins" on a viewscreen, and then use "a duplicate of Alan Scott's power ring" to flee to Earth-Two with his forbidden knowledge, while the Earth-One universe is annihilated. However, the two Green Lanterns team up and defeat Krona, who is once more consigned to the outer depths of space.
As noted earlier, the base plot is nothing special; what's impressive is the way Broome had merged several myth-motifs into one cohesive story.
At the time of the story's publication, Broome surely knew that most of his readers would stem from a Judeo-Christian tradition, so that he also knew that he would not rock any boats by suggesting that the Hand of God had shaped the universe. To my knowledge there are no canonical stories in that tradition in which God punishes mortals for looking upon him or his works, though a few stories, particularly that of Noah, loosely suggest such transgressive tropes. In the other myth-tradition best known to American audiences-- the interwoven threads of Greek and Roman mythology-- mortals are also never in a position to look upon the creation of the universe. However, since the Greco-Roman gods are anthropomorphic, mortals are able to invade the gods' privacy in other ways; not least being the tale in which the mortal Actaeon intrudes upon Artemis while the goddess is bathing.
However, the one relevant myth shared by both traditions is the origin of evil, and in both cases, a female did the dirty deed. I've already referenced mankind's fall from Edenic peace, which was laid upon Eve, but the Greek myth of Pandora is morphologically closer to the Green Lantern story, in that evil is actually released as a miasma that infects the cosmos, if not as specific demons. And yet, the first metaphor Broome uses to typify the polluted universe resonates with one of the prime narratives that befalls Adam and Eve; that of "brother killing brother" (page 8).
No less mythologically intriguing is the name Broome confers upon his villain. Krona is almost certainly derived from the Greek god Cronus, whom the Romans later conflated with their deity Saturn.
In Greek myth, Cronus can be compared in some particulars with God-the-Creator. Cronus doesn't spawn the cosmos, but he makes the ordered cosmos possible through the slaying of his father Uranus, who refuses to let Cronus and the other Titans come forth from their mother Gaea (at least in one version of the myth). After Uranus is deposed, Cronus and his sister Rhea rule the world of the Titans and maintain a Golden Age for a while-- another pre-lapsarian period, which appears in Broome's story as the "ten billion years ago" era of the Oan people, who apparently start out as immortals and live in a universe free of evil. Broome even furthers the comparison to the Greek Titans by saying on page 7 that "[The Oans] strode [their] planet like giants," though there's no suggestion that any of them are literal colossi.
The end of Cronus' Golden Age comes when he hears a prophecy that one of his offspring will overcome him, at which point he more or less emulates his father-- this time, not confining his offspring to their womb but devouring them as soon as they come out. Thanks to some trickery by Cronus' wife Rhea, Cronus' destined usurper, his son Zeus, survives, kills Cronus, and frees his siblings from Cronus' stomach.
So Cronus' transgression against the orderly cosmos is that he, like his father, tries to cut off the next generation. In one sense, this seems a very "male" thing to do, on a par with alpha-male gorillas who take over a tribe and slay any children born by alphas other than him. Certainly it seems to be opposite to the sins of Eve and Pandora, which both boil down to feminine over-curiosity. And yet, though Broome's Krona has no interest in spawning children, or even ruling anything, he does seek to destroy the entire cosmos in a manner analogous to Cronus' suppression of the newborn gods-- and he does it for the same sin evinced by Eve and Pandora: that of curiosity. Yet in many ways Krona is also in the tradition of the curious male-- not so much bumbling swains like Actaeon, but more along the lines of Victor Frankenstein, whose name has become synonymous with that of a science that trespasses on the precincts of God.
I should note also that Zeus does not slay Cronus right away as Cronus implicitly slays Uranus: once the other gods are freed from Cronus' gullet, Zeus leads them against the Titans. This results in the cataclysmic war of the Titanomachy, from which the gods emerge as the new rulers while the Titans are consigned to Tartarus-- once again, imprisoned within a womblike Earth. The cataclysmic battle between "the favored gods" and "the gods no longer in favor" is arguably translated into an ongoing battle of "good" and "evil" in popular fiction, not least the "Lensmen" novels of E.E. Smith, alleged to have been a strong influence on the Hal Jordan corner of the DC cosmos. It's almost surprising that Broome, who had created Qward, a "universe of evil" in GREEN LANTERN #2, did not reference that universe in "Origins." And yet it's not truly surprising, given that comic-book creators avoided overly complicated scenarios, since they were writing so as to catch the vagrant attention of kid-readers. Later writers would inflate the opposition of the Oans and the Qwardians to the point that the two groups became the structural kindred of E.E. Smith's warring alien races. But to his credit, Broome, unlike many later comics-writers, had some intrinsic understanding of the myths he evoked. A lot of comics-writers have conjured up disasters for their heroes to fight, but few, aside from Broome and maybe Stan Lee, have been able to give them mythic resonance:
"Wracked by invisible waves of evil, spreading from Krona's presence on Earth-One, the planet itself goes berserk, seeking in fury and hatred to destroy the humanity that has spawned on its surface."
And this line of thought takes us back to tales of world-wide cataclysm, whether spawned by God or by Zeus-- but that's probably enough myth for now.