A number of subversive organizations in Marvel comic books began, appropriately, conducting their operations in secret from behind the scenes, hidden in shadows while they communicated with and directed their lackeys in the field. Sooner or later, we'd become aware of the name of such an organization (usually from the fearful mention of them by their operatives), which began a steady build-up of apprehension and dread--the organization itself later to be revealed in a dramatic moment which saw it ready to make its power play while our hero(es) stood helpless. It turned out that one such organization, however, carried out its plans right in front of us from the start, their members' identities an open secret, so to speak; yet in this case, the formal name of their group wouldn't be assigned by a Marvel writer until almost twelve years after the fact, and even then with no connection yet established between the two. In other words, there came a moment when the group known as the Enclave would finally be born--but with its origin still a mystery, even though it would turn out that it was one that had long since been solved.
If you're scratching your head at that wording, let's put it this way: It would take several years for a writer to take the (new) concept of the Enclave and attach it to the group of characters we had already seen in operation--a criminal organization that would be developed retroactively, you might say. For its introduction in the present, we would have to settle for a story featuring our old friend, the Monocle, who drops their name for the first time (to my knowledge). As we can see, the Enclave, like its fellow covert criminal societies, makes its debut in shadow--and there it will stay, for quite awhile.
We at least know from that story that, despite the Monocle's resolve, the Enclave is a force to be feared, particularly by those who would seek to betray them. Once the Monocle is dealt with, that story ends with the Enclave's abduction of Medusa of the Inhumans--but it would be nearly three years before the scene would be followed up on, in a brief flashback sequence that seemed intended to retire the concept of the Enclave without ever featuring the group in a single story beyond the snippets we'd already seen, leaving us in the dark as to either their motives or their plans.
The malady Quicksilver speaks of was the susceptibility of the Inhumans to the Earth's pollutants, initially diagnosed by Reed Richards, a problem which was eventually worked around when Reed suggested relocating the Great Refuge to the surface of Earth's moon. As for the war with the Enclave, it seemed that the mad Maximus had set up an alliance with them, with the proviso that he be made ruler of the Inhumans in return. (Assuming there was anyone or anything left to rule after the Enclave's assault, the dope.)
In desperation, Quicksilver transports to New York to gain the Fantastic Four's assistance in the struggle--but when the FF arrive, they learn that at least part of the Inhumans' problem has been taken care of.
And just like that, the Enclave is history. But just for another year, as the 1983 Avengers Annual follows up on the moon migration story to further delve into the machinations of Maximus, apparently having only been thrown into a coma by his final attack on the Enclave and now deciding to let bygones be bygones with this ruthless organization. After the Great Refuge was moved to the moon, Maximus becomes incensed that the Inhumans have been forced to abandon Earth because of humans, beings he's always been fervent to eliminate from the planet--and he decides that the Enclave may still prove useful in a new plot to accomplish the decimation of the human race. To that end, he uses his latent mental abilities to switch minds with Black Bolt and then re-establishes contact with his former allies, hoping to use their expertise to attack Earth from the safety of the moon--eradicating most of the population by meteors so that the Inhumans would be free to return, ridding the world of its man-made pollutants and once again reclaiming their home. (And you wondered why he's known as "mad" Maximus.) But Maximus' ruse as Black Bolt is discovered, and the real Black Bolt regains his own identity--and the next stop is confronting those who make up the core of the Enclave, revealed at last to be characters who by this point have sixteen years of mileage under their belts. But they're probably not at all what we might have expected.
Yes, the Enclave turns out to be the name finally chosen for the small group of scientists who once attempted to create a new race of human beings from their citadel known as "the Beehive," in a Fantastic Four story written nearly two decades before. Originally a group of four, each member was a specialist in their own field and who collectively sequestered themselves to dedicate their talents to this one project. We'll let them make their own introductions, as they welcome Alicia Masters (whom they've abducted) and give her the run-down on their operations.
It's difficult to reconcile the goals of "the Enclave" we've previously seen with these men, since before their identities were revealed the Enclave was more involved in espionage and quietly acquiring the reins of power, with an agent like the Monocle an appropriate operative for them. What we encounter of them in shadows appears to be far removed from the men we've just met.
On the other hand, we know in hindsight that the Beehive's scientists were in over their heads, their new breed of man turning out to be more powerful than they expected--so powerful that they couldn't hide their true motives from his mental probing. And we learn that Morlak and the others aren't the altruistic souls that they'd intended for Alicia to believe they were.
Their comrade, Hamilton, fatally dealt with in the conflict with Him, the group survives the assault of their creation and relocates to another facility in order to take another shot at creating their own human being, bringing in Stephen Strange to perform neuro-surgery on their nascent human (using computer equipment) so that this time they'll have a measure of control over their work.
While at first their new creation, "Paragon," seems to be everything the group had hoped for, an unexpected transformation occurs that once again leads to their schemes crashing down around them.
From here, the Enclave goes on to embark in various endeavors, including the assault on the Great Refuge--the genetically altered race of the Inhumans too tempting a target for their experimentation to resist laying claim to. And while it's true the Enclave has proven it will stop at nothing and rationalize practically anything in order to proceed with their agenda, the utter ruthlessness and outright violence they unleash on the Great Refuge (and, later, the Earth itself) reduces their stature to typical world conquerors, who are too busy scorching the Earth to realize that there will be little left of it to salvage and rule.
Once Black Bolt has handily dealt with the Enclave on the moon and its members spend a couple of years in the slammer on Earth, we catch up with them again as they utilize their unique transport grid to extract themselves from prison. And in their bickering, they bring us up to date on their status, including an apparent intent to try their luck with a new life form a third time!
But the Enclave's scheme is stopped before it's begun, since the Feds have picked up their trail and are closing in on them just as they're about to taxi down an airport runway. Let's just say that if their professional skills in the laboratory are anything like their piloting skills, we're all in trouble.
As the Avengers are called in to investigate, however, we learn that the strange force erupting in Jamaica Bay is instead an indication of the return of Jean Grey--while the Enclave's discovery was of a decidedly different nature than what the group had attempted to create previously.
And so it goes for the Enclave, as they're shopped around from one title to the next, becoming involved with other characters such as Quasar, Spider-Man, and the Silver Surfer--even gaining powers themselves at one point, albeit briefly. They had also fallen in with Dr. Doom, working for him as a sort of task force that took care of matters in the field while Doom was occupied elsewhere.
It would be thirteen years after the Jamaica Bay incident when the Enclave would refocus their efforts on engineering new life--this time based on the island nation of Genosha, where they experimented directly on the Genoshans. Eventually, they're confronted by both Reed Richards and a Genoshan magistrate, and are dealt with by a weapon which draws them into a virtual black hole and seemingly ends their threat.
The Enclave would go on to reappear, though its three members have arguably run their course by now, never really aligning with the threat potential of the Enclave as conceived--that is, the darker organization that was created before being retroactively rechristened as the organization headed by the scientists from the Beehive. Though perhaps in some laboratory somewhere, they're even now working to remedy that.
The Enclave's little brother--the Trikon!