So , here's what we've got so far.
Supesu
Supesu is the long remnant of a colony ship from the original seeder days, Specifically one of the primary colony vessels from Japan. Due to some sort of malfunction, Engines, atmosphere, meteor impact, or something else entirely. The ship went down on a life bearing, but mostly undeveloped world. Due to damages sustained, the records of the ship, the technology, and the location of their true home world, were all lost.
Rich in forests and mountainous regions, the world reminded the colonists of what they could remember of their original home, in it's ancestral times, and so, with the very limited technology remaining to them, they established a city, and spread out into the countryside of the world as their ancestors had in millennia past back on earth. Many small villages and farming communities were established, and the world was in good shape for a time.
Developing traditional values much like they had been taught themselves before hand, a tradition of passing past knowledge along and revering the spirits and creatures of nature, this led to the acceptance of many races that managed to find their way to the world, or those which had been there beforehand. A number of these were already space faring beings that had decided to settle on the quiet little world before the arrival of humans. Though, it was a home world to none of them.
Residents
A clan of the stranded Akula race happened to be near the shores of one of the great seas of the planet, these had a trade established soon after with the humans, though some of them were more interested in having some food, these seemed the minority, or, at worst, the ones that could not manage the life aquatic for hunting.
A number of Animal demi type, some anthro beings, and even tauric natured ones, also call the world home. Some having multiple tails, and those with higher numbers seem to be respected by those with less, at least in some cases. Some of these beings settle and with the patronage of the humans, viewing them as deities from their distant history, create temples, and even religious followings under themselves.
The World Today
Eventually, after a few centuries of growth, some parts of the planet began to develop ways to recreate some of the technology that had brought them there, using what was left of the ship, and a little help from the cosmic neighbors, the people began to grow. In certain areas at least, like their technological level, so while some places are still simple villages and content with their lot in life, nearer the crash site there is a metropolis of technological wonder by contrast, vehicles, spaceport, skyscrapers, the works. Though this all developed so swiftly, that the visual styles of the architecture remained much the same.
So you are left with a fully modern society, with the aesthetics of feudal Japan. This also leaves room for this to be, not necessarily a home world, but a likely place for those that would be worshiped, or at the least, respected, from folklore. (Kitsune, Tanooki, etc) to have a possible home in lore. While with it not being a home world, but rather that some gather there as a sort of hub world, there is no forcing someone to have any relations to the planet.
It would not be beyond reason for many to find a home here as the guardian of a temple somewhere, those that are, or resemble those that would be, from Japanese folklore, would simply be more likely to be so.
Ninja of The Spider Clan
Supesu is the homeworld of the Spider Clan (Space Ninjas)
Starting as worshipers of spiders in general, but more specifically the Jorogumo of their region, the clan developed techniques inherent to the lore of their arachnid partners, and soon even incorporated them into the clan itself. The spider symbol they chose for the "spider clan" https://en.wikipedia.org/wiki/Nephila_clavata as the name is drawn from the Jorogumo of folklore, a spider woman, that was known for tricking and devouring helpless victims, after binding them in sticky silk, vore right there in the legends,
The spider clan's hideout, Jōren Falls, a hidden wealth of caverns behind a waterfall, spiders abound in the area, and even a few of the tauric variety seem to have made their home there. Making it difficult to approach even purposely unless already one welcomed there. the Jorogumo are known as decievers and tricksters, as well as users of disguise to appear human for the sake of meals or other gains.
The ninja clan has a friendly relationship with the local Jorogumo, even those not directly a part of the clan itself, and use the incredibly strong silk of the arachnid race, to weave the fabrics used in their gear and clothes, lending it strength far greater than any normal materials available to them.
Samurai of The Raven Clan
In contrast to the tricksters of the spider clan, those of the Raven have a more traditional outlook on life, and a strong affinity for the teachings of Bushido. Their armor is nearly as advanced in durability as the ninja clan, but holds more simple technology within, almost entirely defensive in nature, with the exception of a bluspace storage for a variety of weapons, and the capability for space grade internals. They have an affinity for bird themed objects, many motifs on the blades and armor resembling that of wings, feathers, beaks and talons. Though it is currently unknown why due to secretive nature of their origins, it is suspected that they have contact with some sort of Avian race yet to show itself in the spotlight of the universe.
Original post under spoiler