The Nashuto

Once a civilisation of humans that had lived in Cursed Lands, alongside the Martéans and Valkans, the Nashuto were the first of the Cursed Land natives to arrive in The Continent, after being unable to hold their lands against the strength of The Martéan Empire. Those who were taken by the Martéan Empire were forced into becoming their citizens, while the remaining Nashuto ended up living in the southern isles that would later become The Tirmari Archipelago. Eventually they were pushed to The Isle of Beasts, due to being unable to deal with The Knights of Alderhardt on the mainland and the harsh native wildlife. In time, those on the Isle of Beasts would go extinct, with the three vampire mistresses, Kiya Yokura, Maeda and Yutani Yokura, being all that is left of their people.
Those that attempted to capture land for their people on the mainland, or even in the larger isles of the young Tirmari Archipelago, eventually understood the failings of their society, simply becoming citizens of either nation. Those Nashuto, who were forced to be a part of the Martéan Empire, would later end up coming to the Continent as invaders. This meant that, even though the Nashuto no long existed as a separate, human society, many of Nashuto descent are present in the Continent.
The Nashuto's fall can be attributed to a few factors. For one, they lacked the technological advancements in armor that made The Martéan Empire so powerful, as well as their sheer tactical brilliance. They were also not as war like as the Valkans, making their military much weaker as a result, seeing themselves as the peaceful philosophers in comparison to their brutish neighbours. Although they did produce very skilled individuals, their lack of numbers resulting in the loss of land, as well as an inability to deal with the natives of the Continent, when they arrived on its shores.