Welcome to my story, Primal Lust.

The first thing you should do is set the variables for a family name and personal name for your character, though you will probably have to change them unless you get very lucky or already have a story in mind to read...

You also might want to turn on Game Mode. I personally don't plan on using variables but some other authors may, especially since they might write about Ultrabeasts battling, and they can be handy for tracking such things...

I hope you have fun reading the stories, and remember to hit that little 'Like' button!

It is what you, the reader, would know as the year 2251: slightly more than 200 years ago, the Ultrabeasts appeared all over the world. They were like the Kaiju of Japanese cinema in many respects, to the point that some of them were given the same names, but unlike the Kaiju they didn't vanish into the oceans or some remote island, they stayed around and fought among their own, ruining civilization in the process.

We threw everything we could think of at them, poisons, bio-weapons, nukes, the combined armed forces of the USA... Nothing. The nukes didn't even leave them radioactive or bowl them over with the concussive force of the blast. It soon became apparent that the only thing which could hurt a Ultrabeast: was another Ultrabeast.

For the first decade, we moved what industry and elite scientists we could to protected bunkers inside various mountains. This seemed like it was working: Until the ultrabeasts demonstrated their ability to shrink to human size while losing none of their strength or quasi-magical powers...

Finally, in 2066, three young adult women in various parts of the world, left homeless by the rioting and civil wars that erupted in the Ultrabeasts wakes, had a dream of prescient clarity and put themselves in the Ultrabeasts paths, naked and masturbating furiously.

Their names are legend: Yamato Tomoko, last living child of the last Emperor of Japan; Asha, the both greatest and youngest full warrior of the "Swahili Sisterhood" which worked tirelessly to keep the refugees in central Africa safe and out of the Ultrabeasts paths; and Isabella Francesca Maria Velasquez, once a young martial artist in Brazillia, at the time a barely legal age refugee in a mobile colony deep in the rainforest.

The three women stopped the Ultrabeasts in their tracks, the beasts looked at them, and their expressions changed from looks of unthinking RAGE, to calm and collected reason, but overlaid with burning lust. The three Ultrabeasts then each spoke, the same words in three different languages. "Avatar of Gaia, will you take me as your concubine?"

It is believed by many, especially in Europe and the former United States that there were several more such 'avatars', but they refused and Gaia cast them aside, letting whatever might happen to them occur. Those three, however, chose to lie with the Ultrabeasts, and soon found themselves imbued with immense power. They became the first three Warriors, and in due course the first three women to change into Mothers, then Crones. Over the next three months each of them was joined by a Mother and a Crone, and for the first time, the circle was completed. The word went out about how to 'tame' the Ultrabeasts, but it was discovered that there is a major catch to the process: the new Warrior MUST be completely willing, if she is coerced in any way, the Ultrabeasts will hunt down and kill those coercing her...

The Ultrabeasts also became MORE dangerous once 'tamed', in a certain respect. They not only fought less among their own but deliberately sought out areas of high technology and laid them waste. Those who lived in harmony with nature were spared though, and the 'tamed' Ultrabeasts gave ample warning of their approach, bellowing for the people to flee and abandon their technology, for the Wrath of Mother Earth was upon them...

She has a name in almost every culture, Gaia, Izanami, Nut, Rhea, Cybele, Anu, Hecate, Mat Zemlya, and Pachamama to name but a few: The spirit of the living Earth, of the world and all the things which live upon it: and she had had enough of our shit.

Humanity's wanton destruction of habitats and species was over: the avatar spirits of the ancient kings and princes of the earth, the dinosaurs and other great species now extinct, had been called forth from beneath the earth and returned to life, armed with mystic powers beyond all reckoning. Humanity's global civilization of exploitation and destruction was at an end, we were being weighed, measured and culled. Those that survived would live as Gaia had intended, in huts and lodges of grass, leaves, stone, branches, and hides: amidst forests, planes, pebble deserts and all the other great environments of the natural world. However, lest this lesson be forgotten, as it had been after she sank Atlantis, the Ultrabeasts would remain, a permanent reminder of the majesty and power of the living earth.

One last gasp of the technological heights we had reached was permitted as the Ultrabeasts were wooed and tamed and became calm and collected rulers of vast swaths of neo-primitive humans: all the surviving space programs were allowed to put together a colony ship of our greatest thinkers and engineers and send them to Mars. The red planet had once been Gaia's sister, we were informed, and if they could revive her Gaia would be happy to hear of it. No one today knows if they are succeeding, for all radios, telescopes, and such like were smashed or dismantled following the great ship's departure, but we loaded her down with everything we could possibly think of that they might need. So it is hoped by many that civilization, though banished forever from Gaia's surface, lives still on the red planet, even as it tries to turn that world green once more...

In the years since the launch of "The Colony Ship" as it is now known, the world has come to be divided into roughly 60 great territories of the Ultra Beasts. Each of the major islands of Japan is one, China is broken into 5, and Ireland and Great Brittain are two more. Where possible the lines are drawn by major contiguous land masses, or enduring natural boundaries, like the Rocky Mountains or the Himalayas, but where there are only rivers and streams by which to mark boundaries, there is often strife among the ultrabeasts that rule there...

Always the Ultrabeast has at least three lovers: a Warrior, a Mother, and a Crone. The Warriors are his primary sexual outlet, but they will not become pregnant until they turn 30 years old. Then the new Mother will be impregnated by his very next encounter with her and will bear him a son. Whenever they have sex thereafter, if she is not already pregnant at the time, she will be impregnated with another child: which, despite that so many pregnancies should normally ruin her health, she will bear each one easily and without trouble. Not all the pregnancies will result in sons, only the first one is guaranteed to do so: and there is a reason for that. When the woman who bore the babe dies on her 111th birthday, or sooner in some cases, her firstborn son rises to fight the current ultrabeast. If he wins, he becomes the new Ultrabeast: if he loses, he dies: and this is why it happens after his mother is dead, for Gaia understands that no mother wishes to bury her children. When a concubine of a Ultrabeast turns 70 years old she becomes a 'Crone' though she grows no older physically she ceases to get pregnant when she has sex with her Ultrabeast, though if already pregnant on her 70th birthday she will still bear that child without issue.

At any time and for any reason, a woman may become a "renunciate" by cutting her palm and squeezing three (or more) drops of blood onto the ground while reciting the words "By Gaia's Troth I Renounce You." In her native tongue. Few do however for the price they pay is steep. So long as you are "pledged" to a Ultrabeast you do not age, frozen at the moment you first lay with him. You can grow fat, or lose weight, your hair can grow, or be cut, and grievous wounds can leave you with scars, though far less pronounced than any other woman of your genetic makeup would develop from a similar injury. You also gain the ability to grow and shrink like a Ultrabeast, so you can lie with your lover in human or titan form, or anywhere in between. Finally mystical powers in excess of any normal human open to you, and you gain instinctive command of them. When a woman "renounces" their connection to their Ultrabeast, whatever their reason*, all of that is removed along with it.
*(Unless someone attempted to coerce them to renounce him, in which case the words and blood of the ritual instead call Gaia's wrath against the traitor who is instantly sucked down into the ground below and buried alive, along with any accomplices...)

Still, it is done occasionally, especially if a woman who was pledged to a Ultrabeast falls in love with another, for while she is pledged to the Ultrabeast she can bear his children and no other...

If the Ultrabeast has all of his lovers which are from one category, Warriors, Mothers, or Crones, renounce him, die or change category, at least one new person of each missing category must be found within the year. Should there be no one willing to replace them the Ultrabeast slowly loses their sapience and then after a decade, dies. When that happens their remaining other lovers also lose their powers...

This is one of only three things which can kill a Ultrabeast: the other two being starvation or a battle with another Ultrabeast. However, the Ultrabeasts rarely fight to the death, unless they are a "Bonus Daughter"...

It has happened less than two dozen times, but it is a known phenomenon: sometimes, a Mother's first pregnancy results not just in a son, but fraternal twins, a Son, and a Daughter.

When the twins mother dies, the son will fight his father as usual, but the Daughter ALSO transforms, into a new Ultrabeast. However, usually they don't fight their father, they move away to some nearby area and fight its Ultrabeast. If they win they become the Ultrabeast of the region, growing a penis and testicles in addition to their vagina, and must try to sway the humans of the region to accept them or suffer the fate of a rejected Ultrabeast.

However, the people would be well advised to accept the change in leadership, because when a rejected Ultrabeast dies, the next new "Mother" of every adjoining Ultrabeast will have "Bonus Daughters" who will fight over the vacant territory until one of them is accepted as the new ruler. (Keep in mind, they need not necessarily take their lovers from the region they rule, that's just more typical.)

The results of two Ultrabeasts mating, one normal and one a "Bonus Daughter", have been observed fewer times than can be counted on the fingers of one hand, but it is always the same. The female Ultrabeast convinced the male to mate with her rather than fight and he agreed, both grew to a size compatible with the maximum size of the smaller of the two and they commenced fucking. Precisely an hour later, with both exhausted and the female having cum exactly seven times, the male buried his bone balls deep in the female and came himself. At that point, the male instantly died, collapsed on the ground and by an hour later his body was rotted away to dirt, bone and all. Over the next ten years the female Ultrabeast's belly slowly swelled with the male's final children, and then, in a day-long birthing, the female Ultrabeast gave birth to two new baby ultrabeasts, both "Bonus Daughters", one, like herself, wholly new, the other the spitting image of their father if he was female...

A victorious "Bonus Daughter" cannot become pregnant anymore, but may impregnate with her new male genitalia and still takes pleasure from stimulus to her vagina. Only one "Bonus Daughter", (Yamato Tomoko's firstborn who now calls herself Memai and rules Korea,) has lived long enough to have one of her sons challenge her for her rulership. She slaughtered him like a goat, but while he was fighting her, he was observed to essentially be a masculine version of herself. It is also worth noting that a Bonus Daughter who stands triumphant via mating develops a penis and testicles over the next year instead of a month, but can already impregnate even while she is pregnant herself...

Now, at last, we come to you, the protagonist of this tale. You are a young woman, of an age to have sex and be an active part of your community. You have lived your whole life in a village at a barely iron age level of technology, and even that is suspect because your people do not mine. Rather, all iron that remains is recycled from the ruins of the old order, the collapsed skyscrapers and moldering vehicles of the "before time". You know a little of science, but only that which you need to answer the universal questions: gravity, nutrition, sex-ed, the rhymes and benchmarks to predict tomorrow's weather, and such like. You can read, for reading was not seen as an affront to Gaia, though the books that survived were culled severely.

You also know a little magic: for with magic proved to exist so clearly by the "Years of Encroaching Darkness" humanity has studied it and learned what it can/can not do. Humans cannot call on magic such as the Ultrabeasts possess, (unless they become an avatar,) magic which can conjure great gouts of fire from nothing and render a nuclear blast insignificant, but we can perform lesser tricks of various sorts. With the right prayers to Gaia, we can light dry tinder with a few words and gestures, with special runes dyed into leather we can render it proof against arrows, and with special unguents and prayers draw out the sickness from someone who is ill: even things that could not be cured by the old order, such as cancer. You know how to do all these things, and that is part of why you have been chosen to be the new lover of the Ultrabeast for your region.

By a lengthy selection process, which begins with your uninfluenced affirmation that you come to this decision willingly, you have been chosen to be the Current Ultrabeasts' next lover, and so you go to the place of sacrifice to meet the other Avatars of Gaia...