All participants are 18 years or older.
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To start to understand Mirpetan society, one must first understand the futas, who by far constitute the dominant of the three genders in said civilization; and to understand the futas, one must first know of their origin, the titans from which they (and most Mirpetans) descend. In the days of old, titans appeared to humans as gorgeous eight foot tall amazonian women, who a good number of said humans came to learn, lay claim to two sets of "human" genitalia. Modern futas are those descendants who maintain these hermaphroditic nether regions; while not as tall, if still generally taller than their "human" counterparts (and taller still between their legs), they also generally still lay claim to these general amazonian features, well endowed chests, well toned muscles, and generally pleasing, if intimidating, features.
These futas are both a third gender of a larger whole and a people apart - a futa inseminated by a male, or a female impregnated by a futa, can give birth to (or, in the case of the futa, can also oviposit) one of the three genders, futa, male, or female. However, similar phenotypes aside, the futas are deeply aware of their titan ancestry, historically referring to themselves as a distinct race meant to rule over "human" subjects; confusingly however, the "humans" refer not only to subject nations, but also to the other two genders, males and females. Even with titan lineage, the male and female descendants are indistinguishable, biologically speaking, from homo sapiens, and while there is less available data on the subject, outsiders are fairly certain that, genitalia and amazonian features aside, the futas of modern day Mirpeta are the same.
Before the futas made contact with the humans long ago, they had only each other, when the many tribes and clans were divided against each other, and frequently at war. As was the case of many early human societies, the main purpose of these wars was to take captives; the victorious titan armies would gather the defeated warriors and (to use the direct if contested phrasing) they raped them, each soldier of the winning side taking one of the other. When this was done, each victor who got to take part in such spoils would take their "partner" as captive, bringing them home to join their household. By custom, this captivity was to last for as long as it took for the captive to give birth to the victorious titan's child; from there, the captive had the right to either return home or to join her captor's family as she saw fit. Furthermore, for the time that she was pregnant, the captive, by custom, was expected to be "cared for", which different tribes and time periods understood in different manners.
However, it was commonly accepted that the captor had the right to keep her breeder's penis in a chastity device, while the captor could expect to be "satisfied" by her kidnapper in other fashions, again interpreted differently according to local custom. (Originally, the purpose of these "chastity" devices were particular to titan physiology - as their futa descendants can to this day, titan penises could act as ovipositers, provided they found a receptive womb to impregnate early enough in the pregnancy - but this has not prevented a number of clans in the modern day from frequently keeping this tradition alive with their male household members.)
Then came contact with the human world - the full history of these encounters, the creation of the first tributary period, and the rise of the Mirpetan Empire, we need not go into any detail here. Suffice to say that after taking human males captive on the battlefield, the titans and their futa descendants started taking them and human "breeding" females as regular tribute from the defeated nations, a custom which endured for many generations; eventually however, with the rise of the sustainable futa-based family, the empire transitioned to the modern tributory system which finances the empire, and by extension the modern Mirpetan household, today.
And so we come to the modern Mipetan world - at first glance, it looks not so different from our own present day; there are automobiles and suburban neighborhoods, indoor plumbing and electronic conveniences, television and shopping centers, bustling town squares and cities, office buildings and high rises. But underneath the surface, there are signs that this civilization is technologically advanced (or "magically" enhanced, if such belief systems are preferred by our reader) in ways still beyond our comprehension. To take just one example, a home, once built, can be expanded with a small fraction of the cost, and an even smaller fraction of the labor, used to build it, provided that it is "headed" by a futa and has a proportionally larger "household" living inside of it; in this fashion, the proportional cost of a futa growing her family is only a fraction of what a modern human would have to rise their income by to maintain the same levels of comfort per person.
But as impressive and inscrutable as this technology is, by far the most incredible advances of the Mipetan State are in their medicine (we will be considering their "human" medical capabilities here, as defined above). To start, and put simply, due to widely available nanotechnology, disease is unknown in Mirpetan society; this includes not only every known STD, but everything from cholera to the common cold, effectively a complete invulnerability to all health deterring micro-organisms. (For another example of how advanced Mirpetan technology makes their unique homelife possible, one need look no further than "toilet duty" while keeping this in mind.) This is to say nothing of fantastic healing capabilities - hospitals have been shown to heal deep wounds and broken bones in a matter of hours - and the fact that, with few exceptions, every human and futa are visibly in top physical shape at all times, even when seriously deviating from their otherwise healthy lifestyles from days or weeks at a time, with no ill effect.