Sanjin

Strange things who lurk in deep mountain valleys. Their true origins are unclear. There are various theories about it: some believe they are ancestors of the people who lived in this country, while others believe they are some different kind of strange creatures.

It appears that almost no male sajins have been born in recent years, so the species' population size is steadily decreasing. They also share another characteristic of dying out species: they all essentially look the same, possibly because their blood is thick and their genes are averaging out.