Before High Priestess, there were Magician and Empress. Each was a planetary sized person, meaning that within them, there were four human beings. Thus, they were fifth-dimensional, two dimensions larger than third-dimensional people, within whom there are only two.
Inside the bodies of both Magician of Empress were a man and a woman, each of whom contained another little woman and man inside of them respectively.
Magician was bald with horns. He evolved in line with the planet he formed on, which was characteristically quick and sharp in its movements and properties.
Then there’s Empress, bigger than Magician, not as incisive, but with a staying power than out-endured him.
Empress and Magician were competing for the space in one of the limited number of tracks that orbited a star. The person who occupied this space got the job of refracting light from the sun above down through to the kingdom below. There were only six spots available for this job, and there had been seven of them competing for them, so one had to miss out. All the other positions had been filled; it came down to the battle between Empress and Magician.
So there they are, pushing up against each other in order to get the other one out of the way so they can be the ones to refract the light above down to the kingdom below, a respectable position for planetary-sized beings of the kind that Empress and Magician are.
They’re using all the tools at their disposal to assert their superiority over the other: their bodies are pushing and pulling like sumo-wrestlers; their minds are shooting ideological darts; their hearts are firing chemical weapons, all of which are designed by one of the four particular aspects of either one of their beings to defeat one of the particular aspects of the other’s.
It was mythological warfare, played out one battle at a time in an episodic fashion, with either of the combatants evolving into more and more complex forms capable of more and more refined methods of defense and attack that built on the accumulated knowledge of the previous mythological stoushes and battles that came before.
Neither was prepared to admit defeat, and they spent the epochs of their youth pursuing this mythological conflict, the stakes rising with every stalemate.
Then Magician got the upper hand, and he began to get on a roll.
Empress put her defense to the ultimate test, and Magician learned the extent of his power as his four inner humans evolved to their optimum mythological potential.
His attack passed its peak and began to fade, and Empress remained standing, until finally either of them had exhausted their capabilities, and they stood as equals.
So they decided to share the available space that they’d competed for, and refract the light from above to the kingdom below between the two of them, leaving half of either side of them in shadow.
They got married and consummated their union with a child, the High Priestess, who on the one hand spreads a little bit more of the light above out over a little bit of the parts of her parents that are in shadow, and on the other acts as a safety buffer for Empress, so that if Magician decides to go back on the attack, she can deflect a portion of the energy used to fuel this attack down to High Priestess, making it a certainty that neither one of them is capable of solely occupying the space from then on.
Thus, a whole new mythological era with a whole new set of mythological elements began…