Coming of The Transcendents (T for M/F)

[Transcendent Su]

It is 120,000 years after humanity as begun to explore the galaxy and colonize new worlds.

Most planets have regressed with humans living caveman like existences all the way up to The Expanse like technology. Only a small percentage of humanity's descendants have transhumanist and star trek tech.

Your planet was discovered by The Suterran Transcendency. A Theocratic interstellar empire dedicated to spreading their belief that males and females are inferior genders who are better of being owned by a Transcendent Master Gender. How they go about annexing the planet and converting its people depends a great deal on how advanced they are.

These "aliens" appeared in your skies a few months ago. They landed several ships in the capitals of the various nations of your world and offered to trade their goods and services to the countries that allowed their missionaries special privileges so that they could spread their faith (extraterritoriality among them). Nations that accepted found themselves quickly enriched. The nations that rejected found themselves quickly conquered by their neighbors using super weapons from the stars. Their entire populations were loaded into space ships and sent off to temple markets on distant planets.
The Suterrans explained that they are not aliens in the regular sense of the term because your people and they have a common ancestor, the humans, who left their planet, Earth, thousands of years ago. The Suists explain that their ancestors long ago engineered a new, third, superior, gender. A master gender with the best of males and females with none of the weaknesses.  Over the millennia they have intelligently designed themselves to be superhuman in every respect. They assure people no one will be forced to convert, though they seem to be flexible by the definition of force. The Suterrans secrete a variety of drugs at will, a feature they use to aid in people's conversions. They are all incredibly rich, casually spending millions of dollars like it is nothing. When the transcendents appear in public it is often with a few scantly clad males and females in tow on a leash.

Does this scenario interest you?