Elevator Pitch Version

Torei is a far-distant planet in a far-distant future, and feels like Aeon Flux meets Gor.

Slavery and Stories

Torei is a planet where sexual slavery is common, and in parts of the planet unavoidable.  Many of the stories are told from the perspective of off-world visitors, as this allows the strangeness of Torean society and law to be highlighted without long info-dumps.

History

Initial Settlement

Torei was originally settled by robotic craft carrying human genetic material and incubator units.  This is somewhat like the "Americanos" in Alestair Reynolds's Chasm City.  The robots handled initial terraforming, and then raised the first generation of vat children to start the human population.

Unfortunately, the world of Torei was the last possible planet the settlement craft reached after a number of failed attempts to build in other star systems.  By the time they reached touchdown on Torei, most of the genetic stock was damaged, and the new population was in danger of not reaching sufficient genetic diversity.

Early Human Society

The first generations of Toreans were ruled by the AI terraforming systems, and spent most of their time working for self-sufficiency for both human and machine alike.  The two towering atmospheric envelope devices at either pole needed constant maintenance, and few ever strayed from the terraforming complex they were born in.

Since genetic diversity was low, the AIs insisted on a strict breeding program.  Choice of mate or marrying for love was out of the question, and sometimes residents would be transported from one pole to the other to keep the mix strong.  You could be working on doing good work to make the planet habitable, and find yourself deported to the other side of the world to carry someone's babies.  

Human Self-Sufficiency

The lean years gave way as the terraforming created a fertile band around the equator.  Human families moved out to start a more agrarian life, and formed tribes.  The equatorial societies formed separately from the two polar nations, but maintained trade: mostly trading food for industrial goods.

The contact with the poles also meant that they continued the calculated breeding programs, and tribal elders would decide who mated.  The system shifted from a polyandrous one (multiple fathers mating with a mother to increase genetic spread) to a polygamous one (one father mating with multiple mothers to increase total birth yield).  With food now becoming plentiful, the population boomed all over the planet.

The Old Ways Persist

With breeding programs no longer strictly necessary, and with the population largely stable, it would have made sense to stop the practice.  Instead, existing power structures corrupted and began to grant desired mating as a favor to the wealthy or powerful.  Over time this form of bribery or corruption moved above the table, becoming a legitimate business transaction.  Eventually most women were treated as imprisoned slaves from the moment they were sold by their families.

Equatorial kingdoms flourished, while the industrial polar complexes remained static.  The terraforming systems reached a steady-state, but the habitat never stabilized as expected.  The AIs changed their plans from one of conversion of the planet to one of maintenance of habitability.  The climate by and large remained fixed from that point on.  Surplus capacity was put toward development of rust-belt factories around the tropics, to take advantage of trade with the equatorial tribes.

The Middle Period

Equatorial tribes became kingdoms and then empires.  Fights became wars.  The largest empire to unify the planet existed during this time, covering most of the northern tropics and the entire ring of the equator.  

It was during this time that the Torean equivalent of a Queen Elizabeth the First character appeared.  An accident of succession left the emperor's primary consort with the throne, and she became known as the Princess Thrall.  Much of the high art on Torei (think the role Opera has today) is often a ritual retelling of her life.  

She held on to power by collaring herself at her coronation, and declaring herself a slave to the will of the people.  Her life had trained her to be good at keeping men from staying angry, and keeping people pleased.  She used this and her feminine cunning to keep the lusty local lords happy with her even when they rattled sabres with one another.  After her betrayal and exile to the South, the empire soon fractured and reverted to smaller kingdoms again.

Interstellar Contact

Centuries after its initial settlement, the frontier of the mainstream human interstellar civilization finally reached Torei.  The ring of equatorial kingdoms (or "ringdoms") took advantage of the fact that space elevators work best at the equator, and began to agree to treaties with the larger federations and empires of the galaxy.  Trade with off-worlders meant that new and exciting technology was now possible, and the polar terraforming nations no longer had a monopoly on industrial production.

Treaties were signed protecting the rights of off-worlders to be judged by their own law.  Regions of the planet were devoted to vast skyscraper resort complexes to house and entertain them.  Torei appealed to the galactic mainstream as a combination of Prague in the 1990s and Dubai in the 2000s: a raw underdeveloped frontier, but also an opportunity to live coddled in a vast theme park with an enormous servant class to wait on you.

The polar nations, already defensive and insular, had become terrifying places for women after the Princess Thrall's empire fell.  A no-man's land sprang up in each tropic, built and maintained by the AIs complete with dastardly traps for those who would flee to the equatorial ringdoms.  

The new trade deficit with the ringdoms made this problem even worse.  Factories that had once been used to produce necessary goods now were turned over to futile contributions to the terraforming project, or as vast punishment prisons for unowned women that the starved male population could no longer afford.  Most slaves there are wards of the state, kept obedient under the unblinking eye of the machines.

The polar regions need population to help maintain the aging terraforming infrastructure.  They occasionally kidnap people to work the habitat generators, and with the laws as they are that almost always means slave women.  In fact, by the time the no-man's land was built, the Southern nation no longer had any free women at all.