I noted in my mythcomics analysis of "The God Killer" that it was only a part of a greater saga, but that I didn't find the entire story to have the necessary symbolic density necessary for a mythcomic.
"Panther's Rage" is rambling and episodic, and though it's never boring, its myth-themes are not integrated enough to make me list the entire arc..."Five Billion Years" is a similar case. It's the culmination of a long arc involving DC's space-opera superhero and many of his fellow Green Lanterns from assorted planets. If that wasn't complicated enough, the greater arc is tied into DC's multi-feature epic, CRISIS ON INFINITE EARTHS, and works in a lot of DC history seen in stories like THE SECRET ORIGIN OF THE GUARDIANS and THE SECRET LIFE OF STAR SAPPHIRE. (Below is a quick contemporaneous recap of Star Sapphire's origin.)
In addition, this arc proved notable for building up the character of Guy Gardner, the Bad Boy of the Lantern Corps:
Most of these developments, however, relate purely to lateral meaning as I described it in RETHINKING THE UNDERTHOUGHT. The symbolic density of myth comes into being through the mythopoeic potentiality, which aligns itself with a narrative's "underthought" and frequently, though not invariably, is granted greater profundity by its interaction with the "overthoughts" of the didactic potentiality. Lateral meaning describes what the characters experience physically and what readers should understand of its emotional meaning, and so the lateral elements of this story-- things that relate purely to Hal Jordan's romantic problems or his duels with old and new enemies-- are irrelevant to the matter of myth.
The underthought of "Five Billion Years" reveals yet another "secret origin" for the Guardians of the Universe. Although Green Lantern's mentors spend most of their career looking like sexless, hyper-intellectual dwarfs, "Five Billion" hearkens back to their origins as gendered entities-- which begs the intellectual question, "what happened to the other gender?" In short, the Zamarons-- who, since their introduction in John Broome's Star Sapphire origin, were always depicted as all-female-- are called upon to be the missing "other half" of the mortal race that gave rise to the Guardians.
The confrontation of the Guardians and the Zamarons has one extrinsic purpose, to link the events of the GREEN LANTERN comic to upcoming, post-Crisis events like the MILLENNIUM mini-series. However, Englehart is skillful enough to give this "big event" a strong intrinsic meaning, in that the reunion of the two sexes is touted as an evolutionary necessity. One Guardian says:
The race born on Malthus and and developed on Oa and Zamaron must be regenerated to create a new breed of immortal...
But before this can happen, the most prominent Guardian must duel the most prominent Zamaron to prove the former's fitness to mate with the latter. Since the duel takes place in terms of energy-blasts, the event shouldn't convey any anti-feminine sentiments except to those determined to find that sort of thing.
After the head Guardian proves, at least by implication, that he and his fellows still have the Stuff, they and the Zamarons fly off to some celestial plane, telling the Green Lanterns that they too must evolve, so as to be their own masters. Their own personal "devil" Sinestro attempts to tag along in the guise of a Guardian, but he's caught, and confesses, in very Earth-centric terms, that his intention was to become "a lurking serpent in your new and secret haven."
From what memories I have of MILLENNIUM and the somewhat related NEW GUARDIANS title, I don't think the Guardians succeeded in coming up with their "new breed." In any case the little blue men didn't stay away very long, but returned to the GREEN LANTERN within the next twenty issues, prior to its cancellation.
On a minor side-note, Englehart tries to extend his evolution-metaphor into one of Green Lantern's battles, as the hero bests the mentally endowed super-villain Hector Hammond, telling Hammond, "You've reached the far end of your evolution, while I'm still going." But it's at best a forced metaphor at that point. Whatever the long-term execution of the "Guardians have sex" concept, "Five Billion Years" does manage to impart a sense of space-opera grandeur to the proceedings.