Idealists
"Visualize world peace."
Keirsey called the Idealists the “identity-seeking personality.” What he didn't realize is that Idealists stand at the pinnacle of human evolution, perched on the very threshold of our metamorphosis into creatures of pure light-energy. Instinctively the Idealists realize that the way to achieve this wondrous transformation is to become their truest selves. They tried to teach us. They taught seminars about unlocking our potential, wrote books about how to encounter yourself, and offered online sensitivity training–but we wouldn't listen. Now we will reap the consequences of our callous indifference.
When the apocalypse comes, the Idealists will stop dithering around and self actualize en masse. When at last they achieve total authenticity, their bodies will be enveloped in a storm of golden light, then crumble into dust. Meanwhile, their innermost self will spring free and transform into an energy being with powers beyond human comprehension. So long, suckers!
At once these delicate creatures of light will find themselves in a realm beyond eternity itself, a place where the dreams are reality, poetry is creative energy, and the power of true love conquers all. Unfortunately it will be infested with creatures of utter darkness whose goal is to spread evil throughout the universe. A cosmic battle will commence, and the Idealists will fight until a true champion emerges to destroy the darkness forever.
...However.
Not all Idealists will leave earth when the end comes. Some will voluntarily remain so that they might help the suffering masses. Other, poorly developed NFs will not be able to immediately achieve self actualization, and will be forced to remain until they can unlock their inner potential. Whatever the case may be, what happens next will proceed much the same:
First, the Idealist will begin to “sense things” they shouldn't be able to know. This is a precursor to full-blown telepathy. Some will develop powers of healing, foresight, shapeshifting, telekinesis, force field generation and manipulation of the four elements. As the Idealist grows closer and closer to self actualization, their powers will increase. But these abilities will come at a price.
Because NFs are so much more sensitive than the rest of us, their DNA is particularly susceptible to mutations (the more so as they unlock their true selves). On one hand, this means they have a greater-than-average ability to develop astonishing powers. On the other hand, it means they will become mutants. Surprisingly good-looking mutants, granted, but mutants nonetheless.
Many will develop feathery white winglike protrusions on their shoulders (for the less than ideally developed types, these may also be black). Others will develop curious eye colors such as purple, aquamarine, midnight blue and even red (for the less than ideally developed types). Their wide, expressive eyes will glow when they use their powers. Hair color too will change, with many developing white, silver, raven, blue and pink hair. It will also grow longer and thicker. Females will become sleeker and more lithe. Males will become handsomer and develop strong–but not bulky–muscles. They will take to wearing capes and other curious garb that they feel expresses their innermost self.
Alas, mutants are mutants and many hunters will take it upon themselves to destroy these gentle creatures as a pleasure sport or to satisfy their blind prejudice against nonhumans. INTJ Masterminds in particular will hunt down the Idealists with tranquilizer darts, then drag them back to their labs to perform diabolical experiments to extract their powers. Fortunately, most NFs will be saved in the nick of time by daring Artisans, whom they will fall in love with. (The ENFP Furies, however, will be spared by the INTJs themselves, who will find themselves unable to test the Soul Extractor upon the one person with whom they have ever become romantically entangled.)
Since most of the Rationals will have fled to other places, ENFPs alone will consistently be able to find themselves an NT mate. The Idealists could also get along well with the Guardians, but by this time most of the SJs will be inaccessible under half a mile of rock. Thus, the only available partners for most NFs will be the Artisans.
This will work out surprisingly well. For one thing, by demonstrating the correct way not to self actualize, the Artisans will help NFs achieve their goal of evolving into higher lifeforms. (The idea of ending up with a pile of dust for a mate won't worry the SPs as much as it would other types.) When the time comes for the Idealist to transform, their SP mate will recklessly grab them, get caught in the golden light storm, and mistakenly become elevated into a superior being with cosmic powers. Or, they may just turn to dust–it could go either way. One thing is certain: their presence will make slaying creatures of pure darkness a lot more entertaining.
Of course, a few particularly lucky Idealists will encounter another of their own kind. Soulmates for life, when the NFs finally evolve they may unexpectedly flow together into one astonishing creature of unmatched love and power. The prophecies say that it will be one of these light beings that will someday destroy the ancient evil forever.
In the meantime, though, there are medical clinics to run and orphans to care for. Indeed, this will be one of the primary tasks of the remaining Idealists: cleaning up the physical and mental mess left by the apocalypse. In a cruel, harsh world, the NFs bring gentle compassion to the suffering people around them. By example they show us that purity and authenticity are always more powerful than darkness and evil–which explains the success of their jihad campaigns.
Alas, the apocalypse will bring out the dark side in a few less than ideally developed NFs. These red-eyed fanatics would rather lead armies into battle for the betterment of humanity than help traumatized radiation victims. But ultimately the forces of Good Type Development will prevail.
And the so Idealists will continue to strive for goodness and truth. As the last spark of light in a world of darkness and ash, they are our final, desperate hope for the future.