"My work may be garbage but it's good garbage." Mickey Spillane
The first Godwar saw a lot of destruction on this alternate earth. The west coast is now the area where the Rio Grande sits. Most of Texas survived in geographical terms, but the vegetation and general environment has altered. The states of Washington, Oregon, and California were mostly sunk.
The island of the Fae sits atop the ruins of Los Angeles in the middle of the much larger version of the Mississippi, whose course was shoved far west by earthquakes and other phenomena as the gods set off all of the fault lines in North America simultaneously. By the time that the war ended most of the indigenous populations had perished.
So they brought in immigrants from old earth (ours).
These immigrants frequently brought plants, cuttings, and seeds with them to restore the areas. So we end up with odd combinations.
We have giant flightless birds on the Great Plains as well as cheetahs and lions and native species. We also have the survivors of the previous high level society’s genetic engineering experiments.
Trolls, goblins, and orcs were the product of those experiments. The immigrants gave them those names, because that is what they looked like to them. Their original names have, in most cases, been lost.
The gods have been doing a lot of terraforming and are sometimes capricious in picking species and modifying species.