Eusdria: Half-Elf tweak
by Marc SaindonAnother idea to further link Eusdria to Thyatian colonization would be a major schism in Vyalian culture. While Vyalia allied with the Thyatian Empire and even agreed to train humans into Foresters (which you can consider Rangers or Arcane Archers), prolong contact probably caused interesting... "cultural exchanges". Conservative and isolationist Vyalian Elves possibly look down on these unions, while more liberal-minded Elves saw the mingling as an opportunity to increase the birthrates of a dying Vyalian culture, even if the next generations would not be entirely Elves (since mixing the gene pools creates either a Human or an Elf, not a Half-Elf).
After centuries of disagreements, the younger mixed-blood generations decided to join in the colonization efforts of the Thyatian Empire in the Savage Coast, after hearing of a vast forested area.
After settling into Eusdria, the Vyalians petitioned the Immortals for a solution in the long term to avoid recreating a caste system based on one's Elven heritage that had been their homeland's main problem. So Fredar and Fredara intervened, and altered the Eusdrians as their own Half-Elf race. The strife of old times also encouraged many younger Half-Elves to adopt the Hattian culture of the other Thyatian settlers (who were more numerous).
(Image from: https://www.deviantart.com/salvamakoto/art/Link-and-Zelda-excuse-me-princess-632903160)